Moon over Soho is the second book in the Peter Grant series by Ben Aaronovitch.
PC Peter Grant is back and as doggedly as ever. A jazz musician dies of ‘natural causes’, but the magical signature the body gives off, tells him and doctor Wallid there’s something strange afoot. A journalist is horribly murdered by having his penis bitten off. Two separate cases that Grant has to solve, while his mentor Nightingale and his friend Lesley are still recovering from their ordeals connected to his previous cases, his father is getting back into the jazz scene, and a voluptuous woman enters his life.