'Supergirl' Hunts for the Third Worldkiller in "In Search of Lost Time" Preview

The CW has released a preview for "In Search of Lost Time", the upcoming fifteenth episode of Supergirl's third season.

The preview reveals that "In Search of Lost Time" will build on tonight's episode with the hunt for the third Worldkiller, Pestilence. As we discovered in tonight's episode Pestilence becomes Blight, the entity that in one thousand years destroys the planet Winath. As Blight is a threat that the Legion of Super-Heroes has previously faced and defeated, Mon-El (Chris Wood) takes point in coming up with the plan. You can check out the preview in the video above.

As you can see in the preview, Pestilence isn't the only issue Supergirl (Melissa Benoist) faces. My'rnn, J'onn J'onzz's father played by Carl Lumbly isn't quite himself. Tonight, it was revealed that the elder green Martian is suffering from a Martian form of Alzheimer's and based off of the official synopsis for the episode (which you can read here) that illness has some unexpected consequences for people at the DEO as My'rnn inadvertently causes psychic disturbances.

The episode will also catch up with Sam (Odette Annable) and Lena (Katie McGrath). With Lena being the only person aware that Sam is Reign, Lena is attempting to help her friend but as the preview shows, Lena might be out of her depth. It's a situation that Supergirl co-showrunner Jessica Queller recently told TV Line sets up something of a triangle between Kara and Lena -- wish Supergirl being the odd third.

"One thing that we play a lot with in the upcoming episodes is the triangle between Lena, Kara, and Supergirl, because Lena has a very different relationship with Kara Danvers than she does with Supergirl," Queller said. "Something we had never played before that we are really examining and excited about in the upcoming episodes is that Lena and Supergirl are at odds about certain things and a bit angry with one another, but Lena and Kara are best friends. Lena feels the closest to Kara of anyone in the world, so then Kara is suddenly in this position where is sort of living two lives with one of her best friends. And although we've always had to see Supergirl maintain a dual identity, it's very personal when it comes to Lena, and it's very challenging for Kara, and so we're really interested in that dynamic."

Supergirl airs Monday nights at 8/7c on The CW. "In Search of Lost Time" debuts April 23.

Are you excited for next week's episode? Let us know in the comments!