When December rolled around
  Marinette and I have gone out several times now, and now it's Christmas. Every day of late I've been asking myself, "WHAT AM I GOING TO GET HER!?" She is such a nice girl, and I want to get her something nice but simple. I just don't want to overdo it. Wait.... I'll make her something, a bracelet maybe, or something similar.
At the construction store
  I found some rolled metal sheets and a few tools. Luck was on my side, as the person in front of me runs a forge. I managed to convince him to let me borrow it for a day and then went to a jewelry shop and bought a few small diamonds. When I got to the forge the next day I began melting and fold the material into a bracelet shape, and after a while of letting it cool down somewhat, I implanted the small diamonds into it. When I was finished it was a beautiful kind of spiraling metal that gleamed with the diamonds. A day or two later I carved a case for it and added red felt (I've got connections) to make it look better. I rapped it then hid it under my bed in a box for the time being.
Seven days before Christmas
I got a notification from my mind telling me that I had finally located Mrs. Agrest. It appears that she is in China. I grabbed my leather jacket and a few other things, and went upstairs to talk to Marinette. "Hey Marinette, can I come in?"
"Just a second," I heard someone putting something away hastily. "Come in."
"Hey, listen I've got to go out of town for a few days, but I'll be back before or by Christmas," I told her bluntly.
"Do you have to?"
"Unfortunately, yes, I made a promise to someone that I'm going to keep."
"Just don't do anything stupid," she said and gave me a hug.
"No promises," I said hugging her back, "I can teleport, so I'll be as fast as possible." I then vanished from site.
Five days before Christmas
I found my way into the attic of some random store in China. I pushed open a false wall revealing a planing room. On the opposite side of a table there is was a women. "Mrs. Agrest, I assume."
"What do you want," she called.
"Adrien asked me to find and bring you home," I said stepping toward her.
"I can't, not until I'm finished here."
"Is there any way I can help," continuing toward her.
"Why would you do that?"
"When I make a promise, I keep it."
"Then help me take down Jonous Clebou."
Christmas Eve 11:30 p.m.
Mrs. Agrest and I appeared at the door of the Agrest household hold, her in a good dress and me in my armored outfit, and knocked very loudly.
"What?" Nathalie came to the door, saw a both of us, "I'll go wake Mr. Agrest and Adrien." She left then heading in at quick pace, and two minutes later there was a voice saying, "come in."
  We entered and there was a look of absolute astonishment on their faces. "If you'll excuse me," I said a moment later, "I have somewhere to go, so see you around." As I turned the group made a hug pile, with content in my heart I left closing the large door behind me.
  I made my way to the bakery in the morning (took me a little while to completely clean up) and found that they were already awake and exchanging gifts. I entered saying, "sorry I'm late, traffic sucks."
  "David!!" Marinette exclaimed ran and hug/tackled me. I slightly enjoyed it, even the hard landing, then said after a moment, "do you want to keep hugging me, or do you want to open your gift?" I quickly went to the box under my bed pulled out my gift and gave it to her, and she handed her gift to me. I opened my gift and found a wonderfully made leather jacket.
  "David, it's beautiful," she said putting it on, "where did you find it?"
  "Who said anything about buying it," I said putting the jacket on, "This is a wonderful jacket, made by you I assume."
  "You made this... for me," her eyes were in tears of joy.
  "Only the best for you," I told her and kissed her.