Adapted from the book When You Were Mine by Rebecca Serle, Rosaline is a comedy/romance film that tells the untold tale of Rosaline - the ex of Romeo. Kaitlyn Dever stars as Rosaline, an intelligent and witty young woman who happens upon Romeo moving on from her ais and now captivated by Juliet; Rosaline, now scorned, finds herself jealous and concocts a plan to sever their newfound relationship and win Romeo back for herself. However, enlisting the help of those around her, Rosaline's comedic journey to sever their relationship will find her attempts thwarted until she begins to do some introspection and change course to help the lovers.