ECLIPSE'S EX RETURNS — Eclipse receives a call from his ex-lover, Carmen and must revisit his dark past in order to protect the Underground. Reed and Sage comb through some secret files they recovered and find alarming information about Lauren's new friend. Meanwhile, Thunderbird helps Blink open up about her past life and Jace greenlights a special surveillance program with the help of Dr. Campbell. 
Guerra forces Eclipse to help her on another job, this time destroying a rival's shipment of drugs; Polaris and Dreamer follow Eclipse after the former discovered he was lying about his whereabouts, and see him work with Guerra. Thunderbird tracks down Clarice, and offers to help her find the road that her portals were opening to when she was sick. They realize that the road leads to the home for mutants that she lived in as a child, but it is now derelict after SS agents stormed the building and killed its inhabitants. She agrees to rejoin the fight. From the stolen information, the underground learns that Wes has a criminal background, leading to him leaving for another underground group, and that Reed's father may have been involved with Campbell's program to turn mutants when he worked for Trask Industries. Now, Campbell and Turner prepare to send these mutants, called Hounds, undercover within the underground. When a DOJ official attempts to stop the pair from using their illegal actions, one of the Hounds makes her have a stroke.
A fake commercial for "Empower Academy" was shown after the end credits, advertising a school where Mutant children can learn to become 'more then their power'. It ends with a link to a website: empoweracademy.com, which leads to the TV series tie-in site: sentinelservices.com.
Trask Industries is mentioned. Bolivar Trask appeared in the X-Men movie "Days of Future Past" played by actor Peter Dinklage. It is revealed that Reed's father worked there fore 35 years and that the company was shut down in the year 1996.
In the original comics, Campbell's alternate ego, known as Ahab, was the leader of the Hounds in an alternate reality. Rachel Summers, the daughter of X-Man Cyclops, was forced to join them.