An outbreak of apparent kleptomania at a student hostel arouses Hercule Poirot's interest when he sees the bizarre list of stolen and vandalised items. These include a stethoscope, some lightbulbs, some old flannel trousers, a box of chocolates, a slashed rucksack, some boracic powder and a diamond ring later found in a bowl of soup – he congratulates the warden, Mrs Hubbard, on a 'unique and beautiful problem'. Poirot's solution of the petty thefts is unsubtle but effective: once he has threatened to call in the police, Celia Austin quickly confesses to the pettier incidents. She denies, however, the following: stealing Nigel Chapman's green ink and using it to deface Elizabeth Johnston's work; taking the stethoscope, the light bulbs and boracic powder; and cutting up and concealing a rucksack. She committed the lesser thefts to attract the attention of Colin McNabb, a psychology student who then becomes engaged to her. She makes restitution for the crimes and reconciles with her victims. The more important incidents remain unsolved. Celia is discovered dead the following morning from an overdose of morphine. It does not take investigators long to see that her death is murder.=