Fran Kranz, an actor who has worked on Dollhouse, The Cabin in the Woods and on Broadway, makes his directorial debut with this clever, rousing drama.

Two pairs of grieving parents arrive at a non-descript meeting room attached to an Episcopal church.

All parties are anxious. Gail and Jay (Martha Plimpton and Jason Isaacs) are visibly jittery. Linda (Ann Dowd) and her husband Richard (Reed Birney) seem uneasier still.

Without anything that sounds like exposition, Franz’s script reveals that a lawyer and a therapist have arranged for this meeting, and that Richard and Linda’s son was the killer in a high school shooting spree six years previously, while Gail and Jay’s son was one of the victims.

The setting never changes and Ryan Jackson-Healy’s camera is never fussy, details that ought to lend Mass the quality of a filmed play. The performances, carefully calibrated characters, and the unexpected detours in the conversation ensure that the film remains an absorbing piece of cinema, one that locks the viewer in with these angry, bereaved people and their increasingly difficult confrontation.

There is no sense of catharsis here. As Linda says early on in the exchange: “I can tell you everything, but there will still be things no one can answer.” So it proves. Gail and Jay wear their sense of devastation even when their expression aims for something else. Linda, who is as obsequious as her husband is officious, is a knot of defences and trauma. Richard, meanwhile, is an emotional drawbridge.

A brief exchange on gun control quickly coalesces into questions about parenting, red flags, and mistakes. “The truth is we believed we were good parents,” says Linda, “And in some awful, disturbing way, we still do.” A small detail about her son, told in the closing moments, quietly articulates unconditional parental love.

It would be difficult to pick between the fine quartet of performances. There is no grandstanding, even in the “big scenes”, only the weight of what has happened.