Mass protected her and Lioness after Paine tried to kill them. Momma tried to protect Mass but Paine threw her on a gurney and she was flying down the hallways with Mass chasing after her. After Mass saved her, she helped save a baby from the fire Paine started in the hospital. When she returned, her "baby" was in a fight with King and she cheered him on.
When Mass was knocked out by Axel, she said she'd never forgive him (although asked if he wanted to date her daughter Victoria if he was single).
Sometime later she was kidnapped by Paine and used as a way to get Mass' cooperation in his newest plan. After both her son and the Alpha Teens break into Paine's lair, Mass frees her and they go after Paine. After Paine makes a deal with Mass, Momma Rossi saw them taking over Landmark City, with her as mayor and the deal was struck.
With Mass on his mission, Paine tossed Momma Rossi in a trash bin, and effectively betraying her. After the Alpha Teens stopped Paine and Mass, a garbage truck delivered her to the Landmark City dump, head first in the trash.