Appearing in "Catacombs"
- The X-Men
- The Morlocks (First appearance)
- The Hellfire Club
- Wolverine (Logan) (Mentioned)
- Wolfsbane (Rahne Sinclair) (Mentioned)
- New Mutants (Mentioned)
- H.G. Wells (Mentioned)
- Mastermind (Jason Wyngarde) (Behind the scenes)
Races and Species:
- United States
- Japan (Mentioned)
Synopsis for "Catacombs"
Candace Southern returns home to the Manhattan penthouse apartment that she shares with Warren Worthington to discover feathers and blood on the floor. She hears an intruder still inside and calls Professor X for help, but Sunder interrupts the call by confronting Southern. Xavier contacts Nightcrawler telepathically, who is visiting his girlfriend Amanda Sefton in her Manhattan apartment, and explains that Worthington and Southern have been attacked. Nightcrawler teleports to the exterior of Worthington's apartment and sees someone carry the Angel into a subway entrance. Before he can pursue, Southern is hurled through the penthouse window and Nightcrawler grabs her before she falls to the street below, and teleports them both back to safety inside Sefton's apartment.
Later, the X-Men gather at Sefton's apartment, however Wolverine is in Japan and therefore is not available. Storm asks Xavier via telepathic link if Wolfsbane can be made available to assist in tracking Angel's location, but he states unequivocally that New Mutants are students and are not to participate in missions. Instead he suggests that Storm use Mini-Cerebro to track Angel. The X-Men depart to search for Angel; leaving Southern, Lockheed, and Sefton to wait at the apartment.
The X-Men go to the subway platform where Nightcrawler saw the unknown assailant carry Angel; Storm checks the Mini-Cerebro which indicates that Angel is far below the subway station. As they travel further beneath the surface to the Alley, Storm becomes more agitated due to the enclosed space, noise, and filth. Eventually, they are attacked by a group of Morlocks and Storm directs Sprite to scout the area while she, Nightcrawler and Colossus fight off the attackers. Sprite phases through a wall and finds a group of four Morlocks: Sunder, Callisto, Plague, and Masque, who appear to be coordinating the attack. She is quickly discovered and Plague lunges at her; she phases and escapes but feels desperately ill after being touched by Plague. The Morlock attack of the three X-Men breaks off and they continue their search for Angel, leaving Sprite behind, unaware of her situation. They eventually find Angel unconscious and held captive by Callisto who intends for him be her prince. As she moves to cut Angel's pinfeathers to prevent him from flying, the X-Men stop her, but before they can free Angel they are overwhelmed by Morlocks. Elsewhere, Caliban finds Sprite and recognizes her from when he attempted to abduct her and takes her to a bedroom to care for her in the hopes that she will be grateful for his efforts and fall in love with him. However, he is unable to reverse the effects of Plague's sickness and fears that she is dying.
Meanwhile, Tessa has summoned Sebastian Shaw to the Hellfire Club. When he arrives she explains that Emma Frost had wanted to warn him about some danger, but was attacked by an unknown force and fell into a coma before she could communicate the threat. Shaw and Tessa discuss that only a telepath of phenomenal strength would be capable of subduing Frost, but the only person who would seem able to accomplish this is Xavier. Shaw dismisses the notation immediately as the professor is, "too high-minded and honorable."
- Kitty Pryde expresses disdain for her codename "Sprite" in this issue, "I'd ask you to call me by my codename, Storm, if I didn't think it was so dumb." But she does not take the name "Ariel" until some time later.
- Wolverine doesn't appear from Uncanny X-Men #169 to #171 since he is away in Japan.
- Callisto states that the Morlocks took their name from characters in the H.G. Wells novel The Time Machine.
- Mastermind is later revealed to be behind the attack on Emma Frost.
- Caliban first appeared in Uncanny X-Men #148, and is the first Morlock to make an appearance.
- Professor X is reading a book titled Marvel Universe.
- The original cover idea (right) was rejected because it wasn't clear enough that Angel was being held in a subway.