Here's the spoiler free version:
This was a great episode! Without spoiling it too much, "sick mind" has a double meaning that all of you will be sure to enjoy
For those who wish to be spoiled:
After Optimus Prime contracts a virus, Ratchet and the Autobots try to figure out how to save their beloved leader. Arcee and Bumblebee sneak aboard the Nemesis to find a cure for the Decepticon created virus. While they don't find anything in the Decepticon's computer system, they do discover the comatose Megatron. Arcee links Bumblebee's mind to Megatron's so that he can find a cure in Megatron's mind. Bumblebee gets more than he bargained for once he's in Megatron's mind as he's thrust into Megatron's dreamworld version of Kaon and faces the evil Decepticon leader face-to-face. This is an awesome episode that harkens back to the first five episodes thanks to the return of Megatron, voiced by fan-favorite Frank Welker.