It centres on the mistaken identity of a building tenant who is thought to be an IRA assassin.
Each act takes place in Seumus Shield's room in a tenement in Hilljoy Square.
Donal Davoren is a poet who has come to room with Seumus Shields in a poor, Dublin tenement slum.
Donal does not refute this notoriety, especially when it wins him the affection of Minnie Powell, an attractive young woman in the tenement.
The Black and Tans raid the tenement and, at that point, Donal and Seumus discover the bag is full of Mills bombs.