'Supergirl': SPOILER is Mentioned in "Fort Rozz"

On tonight's episode of Supergirl, Kara and an all-girl squad left for Fort Rozz in an attempt to [...]

On tonight's episode of Supergirl, Kara and an all-girl squad left for Fort Rozz in an attempt to make contact with someone who could help defeat Reign, but back on Earth, Alex hears from a surprising contact of her own.

Spoilers for tonight's episode of Supergirl, "Fort Rozz".

Sam (Odette Annable), Lena (Katie McGrath), and Kara (Melissa Benoist) are hanging out at Alex's (Chyler Leigh) apartment with Ruby in tow when Sam, who is set to go on a business trip, discovers that her babysitter has cancelled. Alex volunteers to keep an eye on Ruby, which ends up being the perfect solution, and then Alex reveals a text message from Maggie.

Earlier this season saw the breakup of Alex and Maggie (Floriana Lima) as the two women realized that they could not come to a middle ground on the question of whether to have children. Though they still loved each other, Maggie packed up and moved away, leaving Alex to grieve the relationship and try to move on. When Alex sees the text -- which is simply Maggie asking Alex to find and mail her the passport she left behind -- she confesses to Ruby that she thought she had been doing well to get over her ex, but the text brought back a lot of the pain.

Seeing Alex struggle with the pain of the breakup, even this far into the season, is something that Leigh talked about in a visit to the set of Supergirl previously. She said the show would see Alex go back and forth with her grieving process, just like in any breakup in real life.

"I think there was a fine line, I think there was a balance that we really had to establish in kind of saying, 'OK, we don't want to be Debbie Downers all the time. But at the same time, there's a reality of that's an incredibly significant relationship,'" Leigh said. "I mean this is the first time Alex ever really said 'I love you' to anybody, let alone get engaged and have wedding talking and all that stuff. So, you see her sort of like go forward and go back, and then go forward and go back. I think there's a pretty good balance with that."

Supergirl airs Mondays at 8/7c on The CW.