While the search for the World Killers are underway, it seems that the attacks between Lena and Edge have gotten a bit deadly.
After learning about the World Killers in the previous episode, Kara has these strange nightmares about them. Learning that they might have come on Earth the same way as Reign. Winn and the team search for anything meteor showers in the last 30 years and anything bazzair incidents in the last couple of years. Later Winn shows four suspects that have been in deadly accidents that they came out alive and unhurt. Kara sees one of them and points out the one that she's seen in her nightmare.
Meanwhile, the tensions between Edge and Lena have just gotten serious after Edge's car was hijacked and had to jump out before it drove off the road and exploded. Edge blames it on Lena, while she has no clue what he's talking about. But Edge gets payback for poisoning her coffee.
After being saved by both Alex and Kara, Lena figures out who's been pulling this against Edge...her mother. She visits the warehouse where her mother is there waiting for her hoping that her clues would lead her, which it did. Her mother tells Lena that she plans to stop Edge and finish him after what he had done to her.
Lena tries to stop the attack before her mother could by confronting Edge about what's going on, who's the real person to blame and get a confusion from him about him poisoning her. But it's Edge, he wouldn't do it til it acutely happens with Luther drone attacking. Plus Lena's mother coming and bring out the warsuit.
Kara comes and battles with Lena's mother, but gets help with Mon-El and the two, along with the help of the drones, takes her down. Lena chases Edge but Jimmy comes in as Guardian and knocks Edge to the ground. Lena gets her recorder back that has Edge's confession on it and everything seems to be on a good note after that.
But during the episode, Alex helps Samantha with her problem of not remembering and losing time. With all the test that Alex has process for Sam, it turns out that nothing is wrong with her.
"For Good" was a good episode, had a good mystery story between Lena and Edge about who's attacking who. The Alex and Samantha storyline was really good. The performances was good from the cast and the writing as well. Overall, I give this episode a 8.5/10.
You can catch Supergirl Mondays at 8/7c on The CW.