Payphone! (Sequel to Running up that hill)

Optimus Prime never should have felt the way he did. He felt guilty for leaving Softspark and his sparkling behind. Little did he know, that will be the last time he sees her. Softspark died in birth trying to push the sparkling out.

They called the sparkling Lightstar. She looked exactly like Optimus and Softspark. Currently the sparkling has been upset. She grows 2 times faster than a normal human does. She can already walk and Ratchet cares for the sparkling.

What will happen when Optimus comes back?