Although Callie (Maia Mitchell) and Brandon (David Lambert) have each moved on with their new relationships, tension will still rise between them in the upcoming episode of "The Fosters."

In the episode titled "Highs & Lows," TV Guide reports that Callie will be caught in an awkward situation with boyfriend AJ (Tom Williamson). Brandon and his father Mike (Danny Nucci) will reportedly arrive home earlier than expected and discover a surprise waiting for them inside. This suggests that Callie and AJ might be doing something very private that the others should not see. Out of all people, Brandon will be the one to catch them doing it. This will probably be one of the most awkward situations the exes will encounter.

Meanwhile, Stef (Teri Polo) will finally tell her former husband what Brandon has been doing with his life. Because of his financial problems, he has resorted to any means just to get money. Last episode, his mother found out that he took the SAT for someone else and got paid for it. Brandon also gave his settlement money to Cortney (Denyse Tontz) and both Stef and Lena (Sherri Saum) were furious. They feel that his relationship with her is destructive and must be stopped. Will Mike be able to knock some sense into his son?

Meanwhile, Mariana (Cierra Ramirez) is spiraling out of control. She has been visiting Nick (Louis Hunter) in his group home and listening to his lies. He told her last episode that he would get better soon and that they should not break up. Mariana is confused about everything that has been happening. Her twin Jesus (Noah Centineo) knows about her visits to her troubled boyfriend and forbids her to see him. To cope with all the pressure, Mariana will start taking her brother's ADHD medication.

"The Fosters" season 4 airs Mondays at 8 p.m. EST on Freeform.