Picking up on the same night as last season's finale, Elena arrives home to a nightmare as she discovers Uncle John's and Jeremy's fate. At the hospital, Sheriff Forbes is comforted by Matt, Bonnie and Damon while she waits to hear if Caroline will survive the car accident. After a confusing conversation with Elena about the night's events, Damon is the first to realize that Katherine has returned. Katherine's arrival sends Stefan and Damon on a path to find out what she wants, why she's back, and how much of a threat she is to the people they love. Meanwhile, still reeling from his father's death, Tyler is surprised when his charming and mysterious uncle, Mason Lockwood, arrives to console the family. Sara Canning also stars. J. Miller Tobin directed the episode written by Kevin Williamson & Julie Plec.