Mary (Aya Cash
), who works as substance abuse counsellor, has a serious drinking problem, to the point that she walks up to complete strangers who are otherwise occupied and asks if they want to go for a drink with her. She spends her nights at clubs, drinking until she's wasted.
When she gets into a car one night and crashes it, she is arrested for a DUI and thrown into a cell. Her long-suffering boyfriend bails her out, then dumps her. Mary is fired from her job for obvious reasons, so when she gets a call from her estranged father (John Ralston), asking her to return home to Niagara Falls, she has nothing better to do. Upon arrival, Mary learns he's dying of cancer and wants her to form a bond with her teenaged half-sister Robyn (Sara Waisglass), whom she’s never met.