The heroines Abby and Martha, two sweet old spinsters, mad about religion, at first seem the acme of respectability. But it's they who spark the play's bizarre comedy. Although upstairs the spinsters have one nephew, mad Teddy, who imagines himself a long-dead President of the USA, and another, Mortimer, a lazy theatre critic, their status as pillars of the community is impeccable. But then Mortimer discovers a corpse in a chest and his aunts are exposed as serial murderers, who have poisoned a dozen lonely, old men, burying them in the cellar, after tasteful religious services.