The Green Arrow (Justin Hartley) sends out for reinforcements and Bart Allan, a.k.a. The Flash (guest star Kyle Gallner), Aquaman (guest star Alan Ritchson) and Cyborg (guest star Lee Thompson Young) return to Smallville to help him take down LuthorCorp's secret lab.

During a break-in at the LuthorCorp facility, Bart is captured and tortured by Lex (Michael Rosenbaum) and Clark (Tom Welling) sets off to rescue him but is felled by meteor rock. An alarmed Chloe (Allison Mack) goes to Oliver for help and the newly formed "justice league" springs into action to rescue Clark and Bart.