Oliver returns to Starling City on Earth-2, where he encounters familiar faces while trying to decipher the Monitor’s mission. Meanwhile, Mia and William’s team clash with a new foe.

As an old friend visits Helen, a new mermaid arrives leaving Ryn questioning their motives. Maddie learns the truth behind Ian’s death, as Ben fights for his mother’s treatments. While…

In a small town in Colorado, mysterious disappearances happen every 27 years. Sam and Dean head to the town to investigate and meet two hunters who have a personal vendetta…