Twelve-year-old Sunny St. James navigates heart surgery, reconnections with a lost mother, first kisses, and emerging feelings for another girl.

When Sunny St. James receives a new heart, she decides to set off on a "New Life Plan": 1) do awesome amazing things she could never do before; 2) find a new best friend; and 3) kiss a boy for the first time.

Her "New Life Plan" seems to be racing forward, but when she meets her new best friend Quinn, Sunny questions whether she really wants to kiss a boy at all. With the reemergence of her mother, Sunny begins a journey to becoming the new Sunny St. James.