Here's the season 5 episode guide for Supernatural...
Sympathy for the Devil (Episode 1)
The Apocalypse has officially begun. After a tip from the prophet Chuck, Sam and Dean search for a weapon that is meant to stop Lucifer, and learn why Dean was so important to the angels.
Good God, Y'all (Episode 2)
After Cas departs to look for God, the boys help a town that is being attacked by demons.
Free to Be You and Me (Episode 3)
Sam and Dean decide to split up after an argument. Dean teams up with Cas to find an archangel while Sam tries to lay low and ends up learning about his role in the upcoming battle of the Apocalypse.
The End (Episode 4)
Time to do the Time Warp again. Dean is mysteriously transported to 2014, where the world has been ravaged by the Apocalypse.
Fallen Idols (Episode 5)
The ghosts of famous icons appear to be killing their fans in a town in Ohio.
I Believe the Children are Our Future (Episode 6)
Children's myths are coming to life. Dean and Sam think that the unusual occurrences have something to do with a local boy.
The Curious Case of Dean Winchester (Episode 7)
Someone is running a poker ring where the bets aren't made with money but with years of the players' lives.
Changing Channels (Episode 8)
Sam and Dean find themselves lost in TV land after investigating the murder of a local man.
The Real Ghostbusters (Episode 9)
The boys encounter the most horrifying thing they have ever seen...the first annual "Supernatural Fan Convention."
Abandon All Hope... (Episode 10)
Having acquired a weapon that may stop Lucifer, the boys and their allies go to confront the Devil.
Sam, Interrupted (Episode 11)
In order to help an old friend who is in a mental institution, Dean and Sam allow themselves to be committed, but what happens when they actually start to question their own sanity?
Swap Meat (Episode 12)
Sam ends up swapping bodies with a nerdy teenager, but this switch isn't just a crazy random happenstance: he was targeted for a purpose.
The Song Remains the Same (Episode 13)
Anna attempts to stop the Apocalypse by getting rid of Sam...before he's born. Sam, Dean and Cas have to go back to 1978 to try and stop her.
My Bloody Valentine (Episode 14)
People seem to be addicted to love and are dying because of it. Cas convinces the boys a Cupid has gone rogue, but things are actually more complicated than they first appear.
Dean Men Don't Wear Plaid (Episode 15)
The dead of Sioux Falls are rising...and living normal lives? Sam and Dean have to try and set things right, but things get tricky when one of the risen is Bobby's late wife.
Dark Side of the Moon (Episode 16)
Sam and Dean die...again. After ending up in Heaven again, they have to dodge angels so they can find an angel who may have information on God's whereabouts.
99 Problems (Episode 17)
One small town seems to be taking the Apocalypse in stride, with some help from a girl who claims angels are telling her what to do. Dean begins to reconsider fighting the angels' plan.
Point of No Return (Episode 18)
Bobby, Cas and Sam have their hands full keeping Dean from saying yes to the angels. Then, to top it off, they have to keep the boys' newly resurrected half-brother Adam from doing the same thing.
Hammer of the Gods (Episode 19)
The boys stop at a hotel during a rough storm; what they don't know is the other guests are pagan gods planning on trapping them.
The Devil You Know (Episode 20)
Trusting demons goes against every fiber of Dean's being, but in order to find Pestilence, it looks like he's going to have to trust Crowley, the crossroads demon.
Two Minutes to Midnight (Episode 21)
After confronting Pestilence, there is only one horseman left to deal with, so Dean finds himself face to face with Death. Sam, Cas and Bobby must stop Pestilence's plan to spread a demonic virus.
Swan Song (Episode 22)
Dean reluctantly agrees to go along with Sam's plan to put Lucifer back in his cage, and the final battle of the Apocalypse is finally here.