The O.C. (2003)

S4E7 The Chrismukk-huh?

The cherished holiday of Chrismukkah returns to the Cohens, but Ryan and Taylor find themselves in a bind while hanging up the festive lights. An unexpected mishap sends them into a strange parallel universe where Ryan is nonexistent. Meanwhile, in the real world, everyone is concerned about their disappearance, with the exception of Taylor's mom. As they navigate this alternate reality, they work to restore the balance with the help of a letter from the past, ultimately finding a way back to their own world.