When a derailed train plunges into the Niagara River, Abby Laws must care for her young nephew, who insists he was saved by an impossible cephalopod.
Abby Laws, a buttoned-up Toronto therapist, finds her tightly controlled life upended when her ex-girlfriend, grief counsellor Karina Patel, informs her that her estranged sister Chloe was killed in a train derailment. Abby rushes into town only to learn she must take temporary custody of Chloe's son Ben, the tragedy's sole survivor.
Wary of his aunt, Ben prefers the company of Eli, Chloe's boyfriend, who Abby knows has a history of drug abuse. Complicating everything is Diversus, the one-of-a-kind, otherworldly cephalopod living as a tourist attraction in an aquarium in town, whose relative Ben is sure pulled him from the river to safety and whose existence marred Abby and Chloe's own childhood.
As custody tensions escalate and old wounds threaten to reopen, Abby finds herself at the centre of a complex web of grief: How could Ben be saved by a creature that shouldn't exist? What type of guardian does this traumatized child need now? And where does this leave Abby and Karina, brought back into each other's lives under such devastating circumstances?