Smallville :

After being attacked, Clark wakes up in a mental asylum and is told he has been there for five years due to his elaborate fantasy that he has alien superpowers. In this bizarre world, Martha is married to Lionel, Chloe is also mentally unstable and Lana has chosen Clark over Lex.

Lana begs Clark to agree to a doctor's treatment so they can be together, but when a fellow patient named John Jones informs him that the doctor is actually a phantom and Clark needs to kill him in order to return to reality, Clark must make the toughest decision of his life.