Heroes -- Season Three Premiere

In the beginning, it is revealed that future Peter is the assassin who shot Nathan, he puts present Peter in a company facility and sends Matt to a desert. Nathan resurrects and decides not to expose their secrets. Sylar sneaks into Claire's house, brutally ripping her head open, learning the ability to regenerate after investigating her brain. Hiro's father leaves him a formula, which holds the fate of the world, and a speedster steals it, knocking Hiro unconscious. Mohinder discovers the source of their superpowers, the adrenal gland, and he develops a solution which upon injecting will give superpower to ordinary people; he injects a syringe into his arm and gains super-strength and agility.