Homura was at the couch working on her laptop and sipping oil while she worked when Optimus got a call from someone named Sentinel Prime, Homura wondered who this 'Sentinel Prime' was and what is he like.

"Hey Optimus", Homura asked with curiosity of to know who was Optimus talking to. "Who is this 'Sentinel Prime' and what is he?" She asked as Optimus sat down next to her and told her about Sentinel.
Homura saw his expression saddens,

"Sentinel and I used to be friends back in my academy days along with another by the name of Elita-1. One day...Sentinel found an abandoned Decepticon ship full of unstable energon...And then..."
-Flashback-
"Download my ability! Quick!"

"Ahhh!"

"Elita!!!"

"We have to go back for her!!"

"Optimus, you are hereby expelled from the academy for loss of a fellow Autobot."

"Its all your fault she died...Optimus."
-End Flashback-
Homura felt bad for Optimus even when his voice started to break into sobs and small patters of energon fell from his optics but he felt a hand wipe them away.

"Its not your fault Optimus, I would know that as well. I tried to save my friend from repeating her fate over and over again until...her entire existence was wiped clean...No one knew of her...her friends...or her family at all...I can only remember her." Homura calmly said without breaking into tears Optimus hugged her as she hugged back.

"Thank you for listening, Homura." Optimus said with a smile and notice that she got an email from Sentinel that was somehow on her computer.

Homura opened it up and saw a message:

To: Homura
From: Sentinel Prime

Hey old buddy, change of plans we are coming to your base tomorrow due to Magnus' orders. So I guess...See you soon.

-Sentinel

P.S

Whose Cmail (email XD ) is this?