The Summer I Turned Pretty fans have watched the cast change on and off screen ahead of the show's series finale. Based on Jenny Han's three novels, The Summer I Turned Pretty is focused on a love triangle between Belly (Lola Tung), Conrad (Christopher Briney) and Jeremiah (Gavin Casalegno). In addition to the main trio, viewers have also learned more about Belly's brother, Steven (Sean Kaufman), mom Laurel (Jackie Chung) and best friend Taylor (Rain Spencer).