Mammal is the story of Margaret Brady (Rachel Griffiths) a middle aged woman who lives a mostly solitary lifestyle who’s only real passion seems to be found in swimming. Although she may be an insular person she is a good Samaritan at heart as she does work for the local charity shop, feeds the local stray cats and rents her spare room to anyone who needs it.

Her world is changed when her ex-husband Matt (Michael McElhatton) re-appears to tell her that their son Patrick has disappeared but given that Margaret left Matt with Patrick many years before she is unsure how to take the news. Around the same time Margarets helpful nature leads he to a chance encounter with a young injured boy who she helps patch up but who disappear before she gets a chance to speak with him. The same boy appears again when Margaret is swimming one day and she strikes up a conversation leading to her offering Joe (Barry Keoghan) the spare room she has available until such time as she can find somebody else to rent it. Joe is stand offish at first but will never look a gift horse in the mouth so he takes the room. While her relationship with Joe is developing, he seems to open a maternal instinct in Margaret and almost feels like he is becoming a replacement for her lost son. So their relationship blooms and he begins to open up more but during this period Matt returns with the news that their sons body was found in the canal but he doesn’t want he anywhere near the funeral.

Although she never shows it externally Griffiths reserved performance does a fantastic job of keeping her emotions just bubbling under the surface but with enough showing on her face for you to know she is not made of stone. As Margaret and Joe grow closer their relationship swings back and forth and always has a sexual tension which both seem to want to act on but are reluctant to follow which leads to an almost incestuous vibe between their characters.

Keoghan believably plays the troubled boy who warms to the compassion Margaret shows him while he is still embroiled in his old lifestyle of drug and violence which he doesn’t want to leave behind and with McElhatton appearing more and more in Margarets life as he tries to fill the void left by their sons death there is a triangle of a relationship in play which is never going to end well.

Mammal is not a movie for everybody but if you can tolerate the long silences and dark tone which are used to portray Margarets emotional suffocation then there is a well told and well acted story which deserves a watch if you want something a little different.