The CW has released the official description of the episode “Checkmate,” check it out.
IT’S CLARK VS ZOD IN THE SEASON FINALE – Zod (Callum Blue) unleashes his army upon the world, forcing Chloe (Allison Mack) to call in reinforcements from old friends. Zod tells Lois (Erica Durance) he is The Blur and asks her to steal the Book of Rao from Clark (Tom Welling). Torn between Clark and The Blur, Lois asks Clark to come clean with her about everything but he refuses. Chloe (Allison Mack) and Oliver (Justin Hartley) attempt to reconnect Watchtower’s satellite system in order to fight the Kandorians but to Chloe’s horror, Oliver gets caught on site and disappears. Tess attempts to stop Zod but he leaves her clinging to life. Clark and Zod battle for control of Earth.
PAM GRIER (“JACKIE BROWN,” “THE L WORD”) GUEST STARS AND PHIL MORRIS RETURNS AS MARTIAN MANHUNTER — Tess (Cassidy Freeman) creates an elaborate hoax in order to kidnap Green Arrow (Justin Hartley) and delivers him to Amanda Waller (guest star Pam Grier), who tells him that that the government is recruiting him to serve his country. However, Green Arrow escapes before they can reveal his identity. After Oliver brings Clark (Tom Welling) and Chloe (Allison Mack) up to speed, the three investigate and Clark is surprised to find John Jones (guest star Phil Morris.) investigating Oliver’s kidnapping too. Clark senses that John is keeping information from him. Oliver and Clark are shocked when Tess reveals that Amanda is after something called “Watchtower.” Waller threatens to kill Chloe unless Clark gives her the names and locations of the rest of the Justice League.
DC COMICS’ CHARACTERS HAWKMAN, STAR GIRL AND DR. FATE FROM THE JUSTICE SOCIETY OF AMERICA MEET UP WITH CLARK AND HIS TEAM IN A SPECIAL TWO-HOUR EVENT; PAM GRIER GUEST STARS — A man named Sylvester Pemberton tracks down Chloe (Allison Mack) and tells her he knows about her team of superheroes and needs their help. However, before he can explain who he is, he is attacked and killed by Icicle (guest star Wesley Macinnes). Clark (Tom Welling) and Chloe’s (Allison Mack) investigation leads Clark to the former headquarters of the Justice Society of America where he meets up with Nelson AKA Dr. Fate (guest star Brent Stait), Carter Hall AKA Hawkman (guest star Michael Shanks) and Courtney AKA Star Girl (guest star Britt Irvin). Courtney pleads with Hawkman and Dr. Fate to help her catch the killer that is targeting their group but they are reluctant to resume their duties as superheroes. Clark, John Jones (guest star Phil Morris), Green Arrow (Justin Hartley) and Chloe team up to help the JSA stop Icicle before he murders another member of the group. Meanwhile, Lois (Erica Durance) receives a package from a mysterious agency called Checkmate, run by Amanda Waller (guest star Pam Grier).
JOHN JONES IS SHOT — Clark (Tom Welling) discovers John Jones (guest star Phil Morris) was shot while working as a police officer, so Clark dons the uniform and goes undercover to find the culprit. Meanwhile, Lana (Kristin Kreuk) confronts Tess (Cassidy Freeman) and tells her Lex isn’t the man she thinks he is. Lana’s shocking news forces Tess to reevaluate her position as the head of Luthorcorp.
DAVIS STARTS TO SEE HIS DARK SIDE — Clark (Tom Welling) looks into a recent attack in a theater that may be the work of a serial killer. Suspecting it could be someone who is meteor-infected, he demands that Chloe (Allison Mack) release the names of the people she is counseling at the Isis Foundation, which causes a rift between the friends. Davis (Sam Witwer) fears that his blackouts could mean that he is the serial killer and collects evidence that may implicate him. Fearing the worst, he confesses his suspicions to Chloe.