Overdrive is a Japanese Yume Nikki fangame. The player starts as a girl named 323, staying in a laboratory-ish room who doesn't want to go out of it. She can travel to a world called Outer World by entering the capsule machine in the room. Her purpose is to collect all Concepts in the Outer World. There is an unlockable character named 543, a boy that stays in a patient room and doesn't want to go out, after you find the way to meet him in Outer World.