Thomas's assignment to investigate the series of thefts that have been plaguing a chain of convenience stores brings him in contact with two elderly sisters who have a car accident in front of one of the stores; when Thomas learns that they are at the mercy of a slumlord about to evict them and the other elderly impoverished residents of their dilapidated boarding house, he springs into action and convinces Higgins to host a charity bingo game to raise enough money for them to buy the house; after the sisters disappear with the proceeds of the game, Thomas discovers a link between the women and the robberies.