Sweet 16

Sweet 16 is the last book of the series, Trading Places.

Synopsis
In the last month of August, Kristin and Kaitlyn are enjoying their "substitute" families with the obligation that they are switching back. However, as Kristin prepares for Kaitlyn's summer school final exam, Grandma Lisa finds out about Kaitlyn's identity and urges the twins to switch back fast. As Kristin and Kaitlyn meet up at the Leawood Park with Brandon and Gia, Alyssa follows "Kaitlyn" and is shocked to find out she has a twin. When summer school over, the twins are forced to switch back earlier than they planned. Grandma Lisa reveals to Kristin the shocking truth behind her and Kaitlyn's separation. As the twins' 16th birthday approaches, they use the opportunity to bring their families together to reveal to their parents that they have twin girls.