In 1937, Mary Margaret Joyce is born in the Tuam Home for unwed mothers. After spending her early years in an uncaring foster home, she is sentenced by a judge to an industrial school, where she is given the name Peg, and assigned the number 27. Amid one hundred other unwanted girls, Peg quickly learns the rigid routine of prayer, work, and silence under the watchful eye of Sister Constance. Her only respite is an annual summer holiday with a kind family in Galway.

At the tender age of thirteen, Peg accidentally learns the identity of her birthmother. Peg struggles with feelings of anger and abandonment, while her mother grapples with the shame of having borne a child out of wedlock. The tension between them mounts as Peg, now becoming a young adult, begins to make plans for her future beyond Ireland.

Based on actual events, The House Children is a compelling story of familial love, shameful secrets, and life inside Ireland's infamous industrial schools.