Episode 18 of Supernatural Season 6, Frontierland is one of the best episodes of the season. It’s one of the more fun and humorous episodes, with a monster-of-the-week storyline. However, it adds greatly to the over-aching story.
Season 6 focuses mainly on Sam’s soul, the Alphas, Castiel’s plan to destroy Rafael, and Purgatory (all of these plot lines come together at the end of the season). In the Purgatory story line, the mother of all monsters, Eve, is released from Purgatory. Sam, Dean, Bobby, and Cas are all trying to find a way to send her back to Purgatory, with little luck.
In the beginning of the episode, Sam shows Dean and Bobby a hidden entrance to a library full of family mementoes and monster lore, where they hope to dig up some dirt on the Mother of All. He knew about this library because he’d been hunting Alphas with the Winchester’s grandfather, Samuel.
Bobby find a mention in a book of phoenix ash killing Eve. While searching for a mention of phoenixes, Dean finds the journal of Samuel Colt (who isn’t related to the brothers), maker of the only gun that can kill demons, the Colt. In this journal, they find an entry saying that a phoenix was shot in Sunrise, Wyoming in 1861.
In Supernatural, angels can time travel, so they ask Castiel to “angel zap” them into the past. He obliges, but they only have 24 hours before they are lost to him.
Western-style and fun, this is a great episode even if you haven’t seen all the episodes prior to it. It doesn’t have much gore or violence, either.
If you like this episode, other Season 6 episodes you might like are #9, “Clap Your Hands If You Believe” and #15, “The French Mistake.” Some other recommended funny episodes are listed in Recommended Supernatural Episodes for a Sensitive First-Timer. I really recommend Supernatural.