Wikipedia
Gaudy Night
Gaudy Night (1935) is a mystery novel by Dorothy L. Sayers, the tenth in her popular series about aristocratic sleuth Lord Peter Wimsey, and the third featuring crime writer Harriet Vane.
The dons of Harriet Vane's alma mater, the all-female Shrewsbury College, Oxford (a thinly veiled take on Sayers' own Somerville College), have invited her back to attend the annual ' Gaudy' celebrations. However, the mood turns sour when someone begins a series of malicious pranks including poison-pen messages, obscene graffiti, the destruction of a set of proofs and crafting vile effigies. Desperate to avoid a possible murder in college, Harriet eventually asks her old friend Wimsey to investigate.