The final battle comes when The Void launches a full-scale attack on Nova Academy. The girls must band together to defend their home, but their friendship is strained by betrayal and heartbreak. Scarlet unleashes the full extent of her fire powers, burning through the enemy forces, but is consumed by guilt for losing control. Natasha struggles with her own mind as the repeated teleportations begin to tear at the fabric of her reality. Carol flies into the sky, battling the alien machines sent by The Void, all while trying to protect her friends on the ground.

But it is Jean, caught in the battle between herself and the Phoenix Force, who makes the ultimate sacrifice. In a desperate attempt to save her friends, she unleashes the full power of the Phoenix, destroying The Void's army but also herself in the process.

Just when the girls feel they are starting to master their powers, a twist shakes their unity. The Void manipulates one of their own—Natasha. They reveal that her teleportation powers are slowly destroying her mind, and they offer her a solution in exchange for betraying her friends.

Torn between loyalty and fear of losing herself, Natasha makes a deal with The Void, leading them to a secret base where Jean is kept while trying to control the Phoenix Force. During a mission to rescue Jean from the corrupting power inside her, Natasha betrays them, giving The Void access to Jean's cosmic abilities.

Carol: (grabbing Natasha by the arm, angry)
"How could you? We trusted you!"

Natasha: (tears streaming, voice shaking)
"I didn't have a choice... they said they could fix me."

During a confrontation with The Watch, the girls were attacked. Jean, struggling with the Phoenix Force's control, tried to hold back her immense power but failed. The cosmic energy exploded, causing chaos. It was then revealed that Jean had been working with The Watch to suppress the Phoenix.

Scarlet: "You were supposed to be one of us!"
Jean: "I did this to protect you. You have no idea what it's like... to fight this... force inside me!"
Natasha: "You didn't trust us! We could have helped you!"

As the battle between them raged on, Jean lost control, the Phoenix fully awakening. She turned on her friends, consumed by the cosmic power within her.