When a cyber attack brings Starling City to its knees, Oliver and Felicity are pushed to their limits to contain the destruction. Life gets even more complicated for Felicity when her mother, Donna, stops by for a surprise visit. Meanwhile, Ted Grant questions Laurel's motives, and Thea buys an apartment with Malcolm's "estate" money, which infuriates Oliver.

Oliver must stop an Arrow-obsessed serial killer, Carrie Cutter, who is convinced that The Arrow is her one true love and will stop at nothing to get his attention. Unfortunately, her way of getting his attention is to kill people. Meanwhile, Ray asks Felicity to be his date for a work dinner with important clients. Thea auditions new DJs for Verdant and meets Chase, a brash DJ with whom she immediately clashes.