Mon-El starts to tell Kara a secret about Daxam but doesn’t get a chance to finish because Jeremiah Danvers shows up and frees them from their cells.
After removing the lead bullet from Mon-El’s leg, he helps them escape. Kara pleads with him to come with them, but he says he has to stay behind, so Kara and Mon-El make their escape without him.
The story of “Supergirl” is a spinoff from the plotline of “Superman” which the world had come to know. Kara Zor-El was sent to Earth from the doomed planet of Krypton as a 13-year-old by her parents Zor-El and Alura. Alura gave her instructions to protect her infant cousin Kal-El and informed her that she, like her cousin, would have extraordinary powers under the Earth’s yellow sun.
Kara’s spacecraft was knocked off course by a shock wave from Krypton’s explosion and forced into the Phantom Zone where it stayed for 24 years. During this period, time stopped for Kara and when the spacecraft eventually escaped the Phantom Zone, she still appeared to be a 13-year-old girl.
By the time the spacecraft crash landed on Earth, Kal-El had grown up and become Superman. After helping her out of the craft, Superman took Kara to be adopted by his friends, the Danvers family.