Spencer is missing, and Aria, Emily and Hanna search for clues to where their friend may be. They know that Spencer hasn't been herself lately, but has she had enough to just disappear? Could "A" have done something to her? When it turns out her family doesn't even know where Spencer has gone to, the girls frantically search for answers, hoping their worst fears aren't true. Where Spencer does turn up, however, makes it seem as though maybe she doesn't want to be found. Meanwhile, Emily gets the surprise of a lifetime when she meets Olympic gold medalist MISSY FRANKLIN (guest starring as herself).