“He didn’t lose it. His heart broke.” That’s how Woods Weston is described, the central character of this deeply powerful drama.

Tommy Flanagan immediately grabs our attention as Woods, a rugged man and former painter full of pain, anger and longing who is taken in off the streets by his concerned son. As we soon find out, the family has been emotionally shattered and estranged by the sudden death of the wife and mother some time prior. Despite his many problems, both emotional and mental, Woods tries his best to put his life with his beloved sons back together.

This impressive feature length debut of writer-director Heidi Greensmith is a soulful, intimate and deeply humane character study, using emotionally loaded moments of intimate conversation, charged glances, explosive outbursts and uncomfortable silences to explore of how grief can affect even the strongest of people.

On the surface it may seem like a rather clichéd story, with its topics of alcoholism, mental illness and grief not exactly unexplored in small-scale cinema. But there’s an admirable sincerity in how the film approaches these topics, full of genuine feeling and emotion that makes the drama feel potent and very real.

Flanagan, an actor of intensity and magnetic presence, is nothing short of fantastic in the lead role, imbuing the character with a great sense of subtle complexity to make sure that we truly care about him, even when – through little fault of his own – he’s being a tyrant to his loving sons.

The character walks around like he’s a homeless lost cause but he actually has a loving family that could provide a stable foundation for recovery, resurgence as a very talented painter and acceptance of life without his wife. His experiences have made him carry himself awkwardly, constantly on guard for danger, but not afraid of lashing out even at the ones who love him most. Flanagan makes sure you really believe in this man’s pain, his wounded regret and desperate longing for what was and could once be again.

In its relatively brisk runtime, Greensmith also manages to powerfully explore the effect Wood’s behaviour has on those around him, including his older son (movingly played by Tom Payne) who’s caught in stasis between looking after his troubled father and vulnerable younger brother and wanting to move on with his own life. A scene where he feels relief when his dad seems to be changing and utter disappointment when he finds that he’s slipped back into his old ways is particularly heart-breaking.

Winter is a sincere, pure and cathartic drama that may be a little rough around the edges but that’s part of its outsider charm; its unshowy filming style and emotional candidness give it an up-close-and-personal power. Set to a stirring musical score by Dominic Greensmith, it deftly explores many things from the crippling hold of grief to accepting your loved ones for who they are. But above all else it powerfully looks at how the past haunts the present and how accepting loss and moving on is easier said than done.