'Supergirl': Alex Gets Protective of Ruby in Inside "Shelter From the Storm" Clip

The CW has released a new behind-the-scenes clip from 'Shelter From the Storm,' tonight's upcoming [...]

The CW has released a new behind-the-scenes clip from "Shelter From the Storm," tonight's upcoming episode of Supergirl.

Last week, Team Supergirl managed to defeat two of the Worldkillers, Pesitlence and Purity, but now Reign is more focused than ever on getting Sam (Samantha Arias) to submit. This leads the Worldkiller to go after the one person in the world that matters most to Sam -- her daughter, Ruby (Emma Tremblay.)

"We are hunting for Reign and while our team is looking for Reign, Reign is hunting for Ruby," co-showrunner Jessica Queller explains in the video above.

However, if Reign wants to get to Ruby she's going to have to go through Alex (Chyler Leigh) first. As Queller explains, Alex has a bond with Ruby that leads her to step up and protect the girl.

"As we've seen over many episodes, Alex feels a real personal connection to Ruby When she finds out that Ruby's in danger and that Lena has put Ruby into a safe hiding place she is intent to go and be with Ruby and protect her there," Queller said.

Alex's maternal instinct is something that has been an important element of Supergirl this season. Early on, Alex's engagement to Maggie Sawyer (Floriana Lima) ended over Alex's desire to be a mom at some point in her life. The breakup was difficult on Alex, but we've seen her slowly come to terms with her choice -- especially after spending time taking care of Ruby while Sam was supposedly out of town on a business trip. In fact, Alex and Ruby have developed such a bond that some fans have even begun to speculate that the girl could end up being in Alex's care permanently should things go poorly with Reign. It's something that may have even been hinted in Ruby's first casting announcement.

Last summer, weeks before Tremblay was officially cast in the role, That Hashtag Show discovered several casting announcements for Supergirl's third season. Ruby's primarily hinted at her ties with Sam and hinted that she'd be a "major recurring guest star" with "a series regular option of next season". Sam, in contrast, was only listed for one season as a "fractional series regular". If Sam does die or succumb to Reign's will, having Alex step in to care for Ruby would make a lot of sense.

She just has to protect her in tonight's episode, first.

Supergirl airs Mondays at 8/7c on The CW. "Shelter From the Storm" airs May 14.