Smallville

Season 9, Episode 3

Episode Title: Rabid

Air Date: 2009-10-09

Overview:

Zod and his soldiers release a virus into the air that turns humans into zombies. The only way to stop it is to make an antidote from the blood of another Kryptonian. After Lois is infected, Chloe pleads with Clark to donate his blood to stop the epidemic, even though it risks outing him to Zod.