On the precipice of a breakup, a couple briefly reunites to euthanize the cat they fostered together. “Cathy Doesn’t Know,” directed by Gregg Kearns, is a naturalistic drama where the hurt of saying goodbye to a pet meets with a fraught relationship. As another friend hovers in the kitchen for moral support, Cathy waits for Adam. When he arrives, the two prepare for the difficult morning to come. They administer Frank, an orange tabby, some medicine, and traverse above the East River to the veterinarian. From the waiting room, the moments pass by as they prepare for the fate of Frank, and their own doomed relationship. “Cathy Doesn’t Know” is a heart-wrenching observation with moments of surprising levity, a timeless-feeling New York City story built around compelling and tender performances. -JM. Director: Gregg Kearns. Cast: Sam Favata, Gregg Kearns, Riel Macklem, Gia Bonello, Rae C. Wright. DP: Brad Porter. Producer: Caroline J Cassidy. Music by Tom Whaley and James Adams.