'Ow' was the first thing Optimus thought as he woke. 'Where am I?' being the second.
The lights not being particularly bright, his optics easily adjusted to the sudden intrusion of light. He looked around but no one was there. He didn't recognize anything in this room. And then he realized there was something wrapped around his wrists. At that point he realized that said something was also attached to the wall. He realized it wasn't just his wrists that were contained, his ankles and neck as well, although the restraints on his neck weren't nearly as tight.
Now he knew what was going on, or at least, mostly. He was a captive of the Decepticons; because really, who else? He couldn't remember how. Maybe if he could spark his memory somehow...
He concentrated. He thought. He remembered. Well, he mostly remembered. He remembered heading off to fight the Decepticons. He also remembered catching up to them at one of their latest raids. He then recalled fighting Megatron... Someone jumping on his back – a few more cons on top – but anything more he couldn't remember. Either way, he was obviously a captive now.
Oh well, it didn't really matter. Optimus would have to hold out on the brutal punishment of being an Autobot– the leader no less – until his troops came to save him.
Because really, how long had the Decepticons ever kept a prisoner? Not long, right?
... Right?