After a man is killed by a package that exploded after being delivered to his home, Maggie, OA (Missy Peregrym, Zeeko Zaki) and their team race to find the shadowy sender and intercept the latest deadly parcel before it reaches its intended victim in the new episode "Brother's Keeper." Meanwhile, Maggie also is struggling to believe her headstrong kid sister Erin (guest star Adrienne Rose Bengtsson) is really staying out of trouble as a new college student in New York.