Plot
The boys are decorating the lair for the Christmas season but as they were busy getting the decorations out of the boxes, they catch the attention of Lillie who is rather puzzled at what they were up to. Raph tells her that they were decorating for Christmas which leaves Lillie even more confused, saying that she had never heard of the holiday before which shocks the brothers so they decide to teach Lillie what they each think is the most important thing about Christmas. Not knowing that Lillie gives the brothers a special gift on Christmas morning.

It was a cold winter's day in New York City and fresh snow had just fallen down, coating the streets or cars as it was December 24th and people were rushing around to shop for Christmas presents with it being Christmas Day tomorrow. The brothers were currently bringing out the boxes upon boxes of Christmas decorations as Leo carried three boxes while Raph was helping by carrying in the Christmas tree with Mikey's help as Donnie opened one box of Christmas decor, it was full of many varieties of Christmas lights.

"Found the lights." Donnie said, holding up a few lines of multicolored string lights and turning to Leo who set down the boxes with the rest labeled 'Christmas Decorations' as the red eared slider looked over at his twin and then heard a thud along with a small yell. "Ow! That's my foot!" Mikey yelped.

"Sorry mike..!" Raph apologized and he then made sure to carefully put the tree down so he didn't accidentally drop it on Mikey's foot again, Mikey went over to Donnie and he helped him out with the decorations while Leo opened one box and grabbed some silvery gold tinsel with a small smile. "I'm calling it boys, this is gonna be the best Christmas ever." Leo stated.

"Oh definitely, let's get started on decorating boys!" Raph said, Donnie grabbed some Christmas lights and Mikey helped as the two started to string the Christmas lights about the lair while Leo was putting up some Christmas bows and a wreath or two as he gave a small hum which left Raph to set up the tree and made sure that they had the boxes of Christmas ornaments at the ready.

Donnie then plugged the lights in and they came on as Mikey gave a thumbs up to his brother before he went to help Leo out, both the blue masked and orange masked brothers then started to use some silvery tinsel to decorate the doorways. "This is looks so cool already!" Mikey chimed.

"Yeah it is. How are the lights coming along Dee?" Leo asked, looking up at his twin who was trying to untangle the next batch of lights. "Getting there..! I keep telling you guys to carefully put these away!" Donnie said, he was then caught up in a mess of light strings as he had to find the end of it so he could untangle himself as Leo and Mikey helped Donnie get untangled once they finished the tinsel.

"Whoa.. what's going on..?" Lillie asked, the brothers looked over and saw their little sister, Lillie had come out of her room to see what the commotion was. Lillie had little stars in her eyes at all the twinkling and sparkling decorations and she then looked over at the brothers with curiosity. "Are we celebrating someone's birthday?" Lillie asked.

"No, we're decorating for Christmas. Isn't it awesome?" Mikey asked, he smiled and he was definitely in the Christmas spirit as he grabbed a Santa hat and put it on his head as Leo gave a chuckle at the younger brother's enthusiastic energy.

"Christ..mas..?" Lillie said, tilting her head as she pondered about the holiday curiously and Leo looked over as Donnie perked his head up as well, looking at the kid as Raph looked over while he held a few ornaments, Mikey gasped and held his face in his hands. "Ohmigosh! Lillie, have you never celebrated Christmas before?!" Mikey asked.

The brothers saw Lillie shake her head no and all four brothers were in disbelief at what they were seeing, Raph set down the ornaments carefully and he japped his head over to the other room as the trio saw and understood. "Lillie, we'll be right back. In the meantime, why don't you decorate the tree?" Leo suggested.

"Alright..!" Lillie chimed, she went to the Christmas decorations and grabbed a few ornaments while the brothers went out of the room and made sure they were in privacy so Lillie didn't hear them. "How could Lillie have not known about Christmas?! The poor kid missed out on so much!" Mikey said.

"She probably never got to experience the holiday first-hand with her real parents, no wonder she's never heard of it." Donnie said.

"Okay, we need to think of something. We can't have the kiddo miss out on this special holiday." Leo said, crossing his arms over his chest as Raph got an idea that formed in his head and he snapped his fingers.

"That's it! How about we show Lillie the best things to do on Christmas? She's bound to like one of em'." Raph said, the trio thought about it but agreed and they then peeked back into the main room as they saw Lillie standing on a step stool to put some of the ornaments higher up even if she had to stand on her tip toes. She then gave a squeak when she was picked up and lifted up to a higher part of the tree where there wasn't any ornaments placed yet. She looked behind her and saw that it was Leo who had picked her up.

"Leon's gotcha!" Leo said, he smiled a little and Lillie giggled but thanked Leo as the group got to decorate the tree with ornaments, lights, tinsel and even a popcorn garland or two. "Okay, only once last piece of the Christmas tree to go!" Raph grabbed the star topper from the box of Christmas tree decorations.

"Lillie, would you do the honors?" Mikey asked, Lillie smiled and she was given the topper as she was picked up by Mikey. The brothers formed a turtle tower, Raph at the bottom of the tower, Donnie was on Raph's shoulders, Leo was on Donnie's shoulders and Mikey was on Leo's shoulders as Lillie held onto Mikey with one arm while her other arm was outstretched to reach the top of the tree.

"I can't reach! Can you get closer?" Lillie asked, looking down at Raph and the snapper gave a nod as he took a few steps closer and Donnie was struggling to hold Leo up. "Hurry, I can only hold this for so long..!" Donnie said.

"Almost there!" Lillie said, she leaned closer and placed the star topper on top of the tree as she smiled. "She's got it!" Mikey said, soon Raph carefully put Donnie down but Donnie lost his grip as Leo yelled and he landed on the ground with Mikey and Lillie, Mikey held Lillie up in the air so she didn't hurt herself but the box turtle did end up landing on Leo and Donnie when the purple masked brother lost his grip.

"You guys okay?" Lillie asked, she was put down on the ground as Mikey got off Leo and Donnie as both twins sat up. "Other than being crushed by Leo, I'm fine." Donnie said.

"Bruised ego much?" Leo joked, Lillie held back a giggle and Donnie glared at his twin who turned away and gave a small whistle as if it was nothing. "Let's light this tree up baby!" Mikey said, he went over and plugged the Christmas tree lights in, making the tree light up beautifully as all five siblings were amazed by their handiwork.

"It's so sparkly..! Like a thousand stars in the sky!" Lillie chimed, she had never seen anything so pretty and she smiled before she got her head patted by Raph and she looked up at her big brother.

"And that's just one of the awesome things about Christmas, there's even more cool stuff." Raph said, Mikey agreed and he then led Lillie to the kitchen as the child followed behind with a small giggle.

Throughout the day, each of the brothers showed Lillie different things to do during the holidays. Mikey showed Lillie how to make Christmas cookies and even his signature hot cocoa, making different delicious Christmas treats as well.

Donnie showed Lillie how to wrap up presents and he had to help her wrap up a present since she got tangled up in some tape and wrapping paper much like how he had been tangled up in the lights, he had to wrap up some presents in secret however.

Leo showed Lillie how to make paper snowflakes after Mikey taught him how to make them when they were tots, Leo cut his folded up paper and he glanced at Lillie who made little triangle or small heart shaped cuts into her folded paper. Both of them opened their snowflakes and Leo's was a classic snowflake pattern but saw Lillie's snowflake was quite unique with the heart pattern.

After several hours, it was getting late and Lillie finished putting her pajamas on as she then went to the art table she had in her room, she grabbed the paper snowflake garland she made with Leo and strung it along the wall of her room. Lillie then gave a sleepy yawn and rubbed her eyes as she eventually heard footsteps and looked at the doorway, seeing Leo. "Alright kiddo, time for bed. I know you're excited, but you need plenty of sleep.. great, now I sound like Raph." Leo said.

"I heard that!" Raph called from his room and Leo chuckled but rolled his eyes, he walked into Lillie's room and he went to her as he picked up the kid and took her back to her bed. Lillie made a sleepy hum as she was eventually put in her bed and Leo tucked her into bed, softly ruffling Lillie's hair. "Night Lil's, see ya in the morning." Leo said.

"Goodnight.." Lillie yawned and she curled up under her blankets as Leo smiled a little before he shut the fairy lights off and saw the nightlight come on, he quietly snuck out of the room as Lillie fell asleep.

Timeskip

Soon, it was Christmas morning and Lillie tiredly woke up as she gave a yawn before she realized that it was Christmas day, her excitement growing.

"It's here, it's here! It's Christmas time!" Lillie exclaimed, she moved the blankets away and put her unicorn slippers on as she then grabbed a Santa hat that Mikey gave her, putting it on. She then ran to the main floor while Mikey was already awake due to his excitement, he woke up Leo first who was still sleeping since he claimed that he was getting his 'beauty sleep' while Raph was woken up by Mikey and Donnie woke up by himself since he set an alarm so Mikey and Leo didn't disturb him.

"C'mon guys!" Mikey said, he went to where the Christmas tree was and Donnie tiredly followed behind while Leo and Raph followed too. They saw Lillie standing in front of the tree, there was a large pile of presents around the tree, some small, some big and even the Christmas stockings were full of different stocking stuffers.

Raph gave Lillie her pink Christmas stocking and the brothers got to grab a present each and sort them by names, Lillie remembered something and set her Christmas stocking aside. "I'll be back in a second!" Lillie chimed, she went to her room and Raph tilted his head in confusion as Mikey grabbed one present he had gotten wrapped in orange wrapping paper and gently shook it, hearing some gentle shuffling or rattling inside the present.

"Yes! I got two more presents this year!" Leo said, he did his count and saw that he got nine presents in total as Donnie rolled his eyes and grabbed one purple Christmas wrapped present. "Well at least I didn't get coal." Donnie remarked.

"Okay, knock it off you two." Raph sighed, he then saw Lillie come back as she carried a rather colorful looking Christmas present, it had red wrapping paper that faded to a orange color and the ribbon around it was blue with purple stars. The brothers went to Lillie and they had never seen a present like that before. "That's a super pretty present Lil's!" Mikey chimed.

"And it's got all our colors!" Leo smiled.

"Is this for us?" Raph asked.

Lillie nodded and put the present down as Donnie pulled the ribbon, making it come undone from the present as Raph then tore the wrapping paper and the box opened. They saw that inside was a framed picture, the picture was of all five of them. In the picture, Raph had Lillie on his shoulders, Mikey was hugging Leo and Donnie in the picture but Lillie made bunny ears behind Donnie and Leo's heads, Lillie made flower crowns for all her brothers.

Raph's flower crown was made of red carnations, roses and azaleas along with a few boxwood plants.

Leo's flower crown was made of blue hydrangeas, morning glories, bellflowers and some waxflowers.

Donnie's flower crown was made of purple anemone, lilacs, purple hyacinths and a few statice flowers.

Mikey's flower crown was made of chrysanthemums, orange dahlias, marigolds and some climbing jasmine plants.

"Aw! I remember this!" Mikey smiled and he thought the picture was super sweet as Leo smiled and he chuckled when he took notice of the bunny ears Lillie did in the picture. "I wanted my gift to be really special, sorry if it isn't all that good." Lillie said.

Lillie gave a squeak as she was pulled into a group hug and Mikey nuzzled Lillie as Raph patted Lillie's head softly. "Are you kidding Lil's? This is the best Christmas gift ever!" Raph said.

"Yeah, probably one of the most sweetest gifts we could ever get from the best little sister ever!" Leo said.

"Exactly Lillie, you chose a gift from the heart! That's what matters!" Mikey chimed.

"Yeah, what they said." Donnie replied, he cracked a small smile and Lillie smiled as she wiped some happy tears away from her eyes.

"Merry Christmas guys..!" Lillie chirped.

"Merry Christmas Lillie!" The boys exclaimed, the group got to open presents and Lillie was happy that she got to spend her first Christmas with her new family, but more happy that the brothers loved the present that she had given them.