* Fall of the Mutants crossover *
When NYC is hit by a blackout during the Fall of the Mutants storyline, Katie decides to descend into the subway system to try to rescue her mother. Alex, Julie and Jack, who are still grounded from their exploits in issue #33, decide to follow her to make sure she is safe.
Katie finds Pestilence, one of the Four Horsemen, attacking commuters on a subway train. She draws the villain's attention away from the subway and back upstairs, but becomes ill when Pestilence touches her. She manages to find her siblings, and by working together, they access their Kymellian healing powers and cure themselves of Pestilence's sickness.
The kids assist Cyclops and Jean Grey in saving people around the city and tracking Pestilence. During their final battle, Julie knocks Pestilence off her horse with the "Julie Hammer" technique. Katie attempts to save the villain, but she is unable to do so when a piece of falling debris hits Pestilence and crushes her. Jean Grey consoles Katie.
The kids return to their apartment before their mother returns home. Katie confesses that she forced the other kids to break their grounding because she left the house. Margaret Power tells her that she is glad that her siblings had the good sense to go after her, and nobody is in trouble.