Seamus is an up and coming video game streamer, about to make the big leap to platform partner. At the same time he begins a romantic relationship with Emma. Their relationship progresses to the point where it's time to meet Concepta, Emma's mother, but something is... off. Overbearing, erratic, and intrusive, Seamus can't help but feel uneasy, unsure what to make of his potential future mother-in-law. Nonetheless, due to unforeseen circumstances, Seamus is forced to move in with Emma and Concepta to keep his career going while he waits for a new place.
Touching on generational tensions, psychological horror, and relationship dynamics, Mammy is a story about those trying to creating their own lives while under the pressure of a matriarch.