Mornington Crescent

Natalia becomes suspicious when items of women's clothing and jewellery are regularly handed in from a stretch of the northbound Piccadilly line. Then Polly turns up asking about a lost bracelet, only to bolt as soon as Natalia asks how she lost it. Befriending Polly, Natalia calls in the help of her friend Jason in the British Transport police who soon suspects something is seriously wrong on the northbound line ...