Supergirl Season 3 Episode 9 Spoilers – Supergirl Tries to Take Down Reign

Supergirl (Melissa Benoist) deals with a biological weapon on the upcoming episode of “Supergirl” season 3.

Titled “Reign,” next week’s episode will see Supergirl look into the mysterious sign that has been popping up all over the city. After doing some investigation, she traces the symbol’s origins to an ancient prophecy and the mark of Reign (Odette Annable) aka the World Killer.

Elsewhere, Lena’s (Katie McGrath) conflict with Morgan Edge (guest star Adrian Pasdar) continues to escalate. The situation forces James (Mehcad Brooks) to intervene and offer some protection, which could also make things much worse.

This week’s “Supergirl” marked the first part of The CW’s “Crisis on Earth-X” crossover featuring the network’s four superhero shows. All heroes came together to attend the wedding of Barry aka Flash (Grant Gustin) and Iris West (Candice Patton).

In the first hour, an alternate reality in which the Nazis won the World War II was revealed. An avenger sporting a costume made their way into one Nazi camp and was stopped by a masked archer. As they fought, one was unmasked and he turned out to be the Earth-X version of Guardian (Mehcad Brooks). Earth-X James eventually died at the hands of the mysterious killer.

The major crossover continues with its part three tonight on “The Flash.” Executive producer Marc Guggenheim recently told TV Insider that fans can expect “a bunch of really fun team-ups, including one scene in hour four [airing Tuesday] where we literally have everyone on the bridge of ­[Legends’ ship] the Waverider.”

In addition, there is a big action scene featuring Supergirl, Arrow and Flash, as well as one pairing that will surely excite viewers. “Seeing Legends’ Sara Lance ­[Caity Lotz] fighting alongside Supergirl’s Alex Danvers [Chyler Leigh] is a total blast,” Guggenheim added.

The third season of “Supergirl” airs every Monday night at 8 p.m. EST on The CW.