Strange Visitor from Another Planet

As Kara rescues a family from a forest fire, she reads a letter that she dictated about Cat's son, Adam. When she later meets up with Alex to talk about Winn, they run into guy who was asking about Cat, who flirts with Kara. The two then see on the TV screen Senator Miranda Crane rallying around an anti-alien propaganda, which James has volunteered to cover. Cat also is upset with Kara when she sees her son Adam in her office who came from Opal City when Kara sent a letter that Cat wrote but didn't finish. Cat threatens Kara for interfering, but Kara (on the verge of being fired) turns things around by offering to have the two dine together by getting them reservations. Outside near City Hall, Miranda's speech continues to draw crowds as Hank (J'onn) and Alex check the area for alien activity when a fast-moving white alien appears and attacks anyone he sees. Alex and Hank races to stop him but he experiences flashbacks from Mars and Alex saves him before he is run over. James immediately uses his watch and Kara (as Supergirl) appears, rescuing Miranda and against her wishes takes her to the DEO headquarters. Alex also questioned Hank about why he froze, and he explained to both Alex and Kara that the attacker is White Martian, part of a subterranean race that wiped out dozens of his people on Mars, including his entire family. Hank wants to handle the it personally, but fears that if he reveals himself to the world, General Lane will take over the DEO. However, Kara tells J'onn she will help him.

At CatCo, Kara helps Cat out with getting to know Adam while at dinner, which later on becomes awkward and as expected does not go well after Adam found out about the letter. James shows photos of the attack to Kara, who notices that the ones taken after she was kidnapped show her eyes glowing white—much like those of the White Martian. Realizing what this means, Kara calls Alex. Back at the DEO, "Miranda" plays mind games with Hank about an alien mole within the DEO and threatens to out the DEO if he doesn't conduct an investigation. When she suddenly mentions that she was attacked by a White Martian, Hank becomes suspicious.

Kara tells Alex that the White Martian is at the DEO, disguised as Miranda. Alex arrives with a gun pointed at "Miranda" just as Hank goes for his weapon, but the White Martian goes on a rampage through the building. J'onn suddenly starts having visions of White Martians taking a race of Green Martians (who are children). Just as Miranda is about to attack, Kara shows up to challenge her only to have the White Martian escape. Kara is then distracted by Cat and returns to CatCo, who is upset over the dinner earlier because of the letter, which prompts Kara to go see Adam personally. After a short talk and an admission from Kara about the letter, Adam agrees to meet with his mother on the condition that Kara joins them. During their dinner, Kara acts as a mediator and after tense talking both Cat and Adam start developing a normal mother-son relationship.

Alex tells J'onn that she felt bad for encouraging him for using his powers and shouldn't be at fault, but J'onn tells Alex about how the White Martians killed his family, including his wife and daughters (he later reveals there were two: K'hym and Tanya) before he escaped. He then noticed a tissue that came from "Miranda" and over Alex's concerns tracks "Miranda" down by hovering above the city using mind control, leading him to her lair located in a sewer. Posing as Hank, he brings Alex and the DEO agents in to capture the White Martian, and stumble upon the real Miranda and rescue her, except for Alex, who fake Crane captures. J'onn telepathically negotiates with the White Martian to exchange his life for Alex's. The four meet up in the desert. J'onn surrenders but Kara stops it, and a battle ensues between all three. J'onn places kryptonite cuffs on Kara so he can kill the White Martian, but Kara talks him out of it. She tells the White Martian they're ready if the millions she claims attacks. The real Miranda is shown on television, thanking Supergirl for saving her and recalls her earlier stance on aliens, saying that not all aliens are bad but they should still be wary.

Later that evening Adam visits Cat to tell her he is staying in town, as it turns out he has a crush on Kara, and immediately asks her out on a date. This prompts Kara to ask Alex about dating tips but Alex tells Kara to have fun. Meanwhile, in another part of National City, a car is dangling along a bridge ready to fall, when Supergirl apparently flies in and picks up the vehicle... then drops it! The event is caught on camera, and the sisters see it.

"Strange Visitor from Another Planet" at IMDb