Desperate times call for desperate measures. Supergirl’s war with Reign is heating up, and the Kryptonian defender of National City is clearly outmatched. That won’t stand for Kara, though, who, in an upcoming episode titled “Fort Rozz,” will assemble a team of heroes and villains to break into the prison and liberate an inmate who might be their only chance at defeating Reign.

RELATED: Legion of Super-Heroes Arrives in New Supergirl Promo

The episode synopsis reads as follows:

SUPERGIRL

“Fort Rozz” — (8:00-9:00 p.m. ET) (TV-PG, V) (HDTV)

SUPERGIRL TEAMS UP WITH SATURN GIRL, LIVEWIRE AND PSI – As Reign (Odette Annable) continues to terrorize the city, Supergirl (Melissa Benoist) teams up with Saturn Girl (guest star Amy Jackson), and the two recruit Supergirl’s former enemies, Livewire (guest star Brit Morgan) and Psi (guest star Yael Grobglas), to form a team for a mission to Fort Rozz to recover a prisoner who has information on how to defeat Reign once and for all. Meanwhile, Alex (Chyler Leigh) babysits Ruby (guest star Emma Tremblay). Gregory Smith directed the episode written by Gabriel Llanas & Anna Musky-Goldwyn (#311). Original airdate 1/22/18.

Fort Rozz has an interesting history in DC Comic canon. Originally established as a Kryptonian military installation in the deep future, Fort Rozz was later retconned to be a Kryptonian prison. The prison served as a waypoint for criminals sentenced to the Phantom Zone. A riot eventually led to the fort being transported to the Phantom Zone in its entirety. It is one of the few places in the Phantom Zone where time passes normally.

RELATED: Supergirl: First Look At Jesse Rath As Brainiac 5

“Fort Rozz” will air on Jan. 22. Returning Monday, Jan. 15 at 8 p.m. ET/PT on The CW, Supergirl stars Melissa Benoist as the Girl of Steel, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers and Jeremy Jordan as Winn Schott, with appearances by Calista Flockhart as Cat Grant and Tyler Hoechlin as Superman.