Ex-employee Finbar Finch served time after a brutal attack on spa owner Elsie Peters during a robbery of the spa's takings that left her struggling with seizures. After his release he returns to the area, vowing to Father Brown to live a new life after God found him in prison. Elsie, her husband Captain Peters and her sister Lola are rattled by his return and tensions run high at an open event being ran that day. Shortly afterward Finbar Finch is found dead, shot in the face; the shotgun used was taken from the spa, and a brooch found at the shooting leads to Inspector Mallory arresting Lola. Father Brown finds a clue in a poem Finch had read, Antigonish.