The New Boy.

Katie is Freddie Freeman's younger sister. Freddie and Katie have always been close but when Billy joins the foster family Freddie spends all his time with Billy. Katie soon finds out Billy's secret and becomes a target for Dr. Sivana. Dr. Sivana kidnaps Katie after seeing her on the news with SHAZAM and Billy must choose between saving the city or Katie. This is kinda a enemies to lovers.