In 2015, Scott Lang arrived at Maggie's house to attend Cassie's eighth birthday party. Paxton quickly confronted him and made it clear that he was not welcome as Lang had failed to pay child-support. They continued to argue, while Lang gave his daughter her birthday present. Eventually, Maggie arrived, intervened and took Lang outside to discuss what he needed to do to see his daughter after Lang had accused him of being an ass-hat. Paxton stood with Cassie as Lang left the party and drove away.
One night, Darren Cross invaded Maggie's house, kicked Maggie out, and took Cassie hostage. Hearing of this prompted Lang to escape and battle Cross once again. With an army of ants as reinforcements, Lang in his Ant-Man suit engaged Cross on Cassie's toy train set. During the duel, Lang and Cross threw sections of the Thomas the Tank Engine toy at each other. As ants attacked Cross, Lang was able to knock Cross onto the train tracks, causing him to get run over by Thomas the Tank Engine. Cross retaliated by throwing the toy at Lang, but Lang knocked the train aside and onto the windowsill. Lang tried to use Pym Particles Disks to enlarge Cross but he deflected them, causing an ant living there and the toy train on the windowsill to grow to gigantic size.
Paxton attempted to rescue Cassie, but the Giant Pet Ant trampled him on the stairs as it was leaving. Eventually, Paxton made it to Cassie and tried to protect her from Cross. Lang continued fighting Cross and decided to go subatomic to sabotage the Yellowjacket suit from the inside, causing Cross to shrink fatally into the Quantum Realm, finally killing him. Lang succeeded, but also became trapped in the Quantum Realm; however, he had an enlarging Pym Particles Disk remaining and used it to reverse the suit's mechanism, successfully returning to normal size. Lang then was hugged by Cassie, with Paxton thanking him for saving them.
Months later, Paxton invited Scott Lang over for dinner in gratitude for having saved him and Cassie. During dinner, Cassie fed the Giant Pet Ant food, which was under the table, acting like a dog.