“Shelter From the Storm” is episode eighteen of season three of Supergirl.
James and Lena are getting dressed in her hotel room and James is talking about her getting her own place when Reign crashes through the window looking for Ruby. Lena drives her off with a Kryptonite aerosol.
J’onn is talking to his father about helping him continue preserving his memories before J’onn sees the Legion off. M’yrnn claims he doesn’t have the energy and just wants the vinyl discs turning on.
On the Legion ship, Imra is saying that the Legionnaires who fell to the Blight were put into stasis to save their lives and left there as they couldn’t risk exposing the timeline to it. But with Pestilence defeated in this time in the previous episode, “Trinity”, they never fell to it and are now healthy. Brainy says Imra needs to return to the future as they don’t know if the Titan Alliance will hold without her.
Brainy tells Winn he originally categorised Winn as a 1st level intellect. He was wrong; he’s a 1.42. He also has a gift for Winn. Dirt. From the 31st century. Brainy calculated Winn would either collect dirt or New York Mets baseball cards and from the last 783 Major League seasons, dirt was more likely to hold its value.
Mon-El and Supergirl are saying goodbye when Alex returns and tells them about the attack on Lena’s penthouse. Supergirl says J’onn will be sorry he missed the goodbye. Mon-El says he will see J’onn in a thousand years., It doesn’t look like he’s joking.
At the penthouse, Lena tells them Reign was after Ruby. She may also go after Patricia. And Lena discovered electricity worked on Reign. Alex wants to go see Ruby. Lena says she’s safe in a place that no-one but she and Lex knows about that can’t be seen from space. Lex’s mansion. Alex heads there. It’s Lex’s invisible mansion.
J’onn and Supergirl head to Patricia’s house to tell her Reign is on the way. Patricia knows Sam is Reign. Sam used to doodle when she was ten and eventually did it on the wall, showing them. Reign’s symbol. Patricia says she was an awful mother as she wanted Sam to grow up normal and if she’s coming, Patricia is going to be there for her.
Alex is being shown around Lex’s mansion on the way to find Ruby. Ruby wants to know if her mother is sick and if Alex knows what’s going on. Alex denies that she does.
J’onn and Supergirl are at Patricia’s and J’onn is talking about how his father is depressed and feeling useless. Then the plants die, because Reign now has the power of the other two Worldkillers. Reign enters the house and heads to see what she thinks is Ruby cowering in a closet. It’s Supergirl, who blasts her out of the house with an electrical weapon. Reign uses Purity’s power as well, knocking Supergirl and J’onn down. Patricia tries reasoning with Sam and badly injured as a result. She forgives her. With Patricia dieting, J’onn and Supergirl get her out of there.
The Legion ship is several hours from the disruption when Brainy comments to Mon-El about Reign absorbing Purity and Pestilence’s powers. He bugged Winn’s dirt. Supergirl has a 51% chance of beating Reign, but the addition of one Legionnaire would increase that to 88.8%.
Mon-El has faith in Supergirl, as does Brainy, but the odds are only marginally in her favour. And Alex going to see Ruby may have been a mistake as she’s a terrible liar.