The Foster household will immediately deal with a lot of overwhelming problems when "The Fosters" returns for season 4.

For its premiere episode called "Potential Energy," Callie (Maia Mitchell) will finally come clean to her mothers Stef (Teri Polo) and Lena (Sherri Saum) about her intimate relationship with Brandon (David Lambert) that happened just before they legally became siblings.

But before Stef and Lena could wrap up their heads around Callie's revelation, another problem will arise. Their children's high school gets locked down when Mariana's (Cierra Ramirez) boyfriend Nick (Louis Hunter) brought a gun inside the campus.

In the sneak peek for the upcoming episode, Nick appears to be in a vengeful fit after finding out for himself that Mariana kissed her ex-boyfriend Mat (Jordan Rodrigues) by the end of season 3. His fury caused him to think irrationally, and it seems like he will do everything to make Mariana know that she hurt him. In one of the scenes in the trailer, Mariana was startled when she discovered Nick inside her room with a gun in his hand.

The trailer also showed that the Stef's life will be in danger as she tries to protect the students. Can the police officer stop Nick from his plans without having to risk Stef's life?

Aside from Callie and Mariana's problems, the Fosters will also deal with Jude's (Hayden Byerly) depression after his friend Jack (Tanner Buchanan) died due to domestic violence. In an interview with Enstarz, Byerly said that his character will be deeply affected by Jack's death.

"You see how that kind of plays a toll on him and what happens and how that affects him," the actor said.

He also added that Jude will "continue to struggle with his balance between being religious and gay, and he'll try to find who he is and he's still going to struggle accepting who he is and come to terms with that."

The premiere episode of "The Fosters" season 4 airs June 20 on Freeform.