Four of our series — Smallville, Supernatural, Moonlight, and Reaper — are airing their season finales in the next week, all but closing out a strange, frustrating, but ultimately encouraging 2007-08 season. Don’t miss these final episodes, which are likely to set up some serious jonesing for shows that won't return until the fall (or, in one case, ever).

The real bad news, though, is that after these four shows close for the season, the only ongoing sci-fi series showing new episodes will be Battlestar Galactica and Doctor Who.

Details on the finales are below (may contain spoilers).

Smallville’s season finale is “Arctic,” airing Thursday, May 15 at 8 p.m. ET on The CW. News: This may be Allison Mack’s last episode; her participation in season 8 is in doubt, but negotiations are said to be still under way (more on that to come); expect “Arctic” to make it possible for her to take off. Kristin Kreuk reappears as Lana, and sets up her reduced presence in season 8. Summary: Kara (Laura Vandervoort) tells Lex (Michael Rosenbaum) he is destined to defeat the Traveler and offers to take him to the Fortress to learn how. Clark (Tom Welling) is stunned that Kara would go to Lex but it is revealed that Brainiac is impersonating Kara and she's actually trapped in the Phantom Zone. Chloe is arrested by the Department of Domestic Security and Lana awakens from her comatose state. Meanwhile, in an epic turn of events, Clark and Lex face off in the Fortress and Lex learns Clark's secret. Creators: Todd Slavkin (director); Don Whitehead & Holly Henderson (writers).

Supernatural brings the story of Dean’s contract to a final confrontation in “No Rest for the Wicked,” airing after Smallville on Thursday, May 15 at 9 p.m. on The CW. News: This is one show where it’s quite possible the imperiled character will actually die (and go to Hell!), so the tension is high. The screws are pretty tight on this story; not much has leaked out, though Dean’s amulet (which got a backstory in “A Very Supernatural Christmas”) may be relevant. Expect Bela (Lauren Cohan) to be more or less written out – she’s not been a hit with fans or writers, and word was the hot semi-regular was imposed on Eric Kripke by the network anyway; the demon Ruby, however, should continue to be relevant. Summary: It's 30 hours before Dean's (Jensen Ackles) deal with the crossroads demon is up and Dean, Sam (Jared Padalecki) and Bobby (Jim Beaver) are searching for Lilith, who holds the contract. They discover her location and Sam summons Ruby (Katie Cassidy) for help despite Dean's protests. Ruby warns them they aren't ready to fight Lilith yet but they steal her knife and depart for New Harmony, Indiana. In a battle to the death, Sam, Dean and Bobby take on Lilith and all her demons in a last ditch effort to save Dean's life. Creators: Kim Manners (director); Eric Kripke (writer).

Moonlight airs the final episode of its freshman season, "Sonata," on Friday, May 16 at 9 p.m. on CBS. News: The cancellation of Moonlight has been announced, so this is the actual close-out of the show. The handwriting was on the wall, so expect "Sonata" to wrap up as many loose ends as it can. Summary: Mick (Alex O'Loughlin) and Beth (Sophia Myles) face the ultimate consequence of a relationship between mortal and immortal when a vampire kills a human in the heat of passion. But when the murder investigation threatens to expose vampire identities, Mick and Josef (Jason Dohring) must take action to prevent exposure. Features the reappearances of Eric Winter (Brothers & Sisters) as ADA Benjamin Talbot, Claudia Black (Stargate SG-1) as The Cleaner, and Shannyn Sossamon as Corraline. Creators: Fred Toye (director); Ethan Erwin and Kira Snyder (writers).

Reaper also closes out is first season on Tuesday, May 20 at 9 p.m. on The CW. News: Reaper has been picked up for a second season (though only as a 13-episode midseason replacement), so this isn’t the end of the story. Summary: The demons target Sam (Bret Harrison) when they fear he may pose a greater threat to their rebellion than the Devil (Ray Wise) himself. A treacherous trap is set, bringing surprising allies to Sam's side and leading to shocking revelations that could have explosive implications for his future. Meanwhile, Sock (Tyler Labine) falls for a demon (guest star Cindy Sampson). Creators: Stephen Cragg (director); Michele Fazekas & Tara Butters & Tom Spezialy (writers).