"Summer Knight" is the fourth book in Jim Butcher's urban fantasy series, "The Dresden Files." In this installment, wizard detective Harry Dresden finds himself embroiled in a dangerous conflict among the supernatural factions of the summer and winter courts. The story kicks off when he is summoned to investigate a murder connected to the fae, leading him to unravel deeper conspiracies that threaten the balance of power in the Otherworld. As Harry navigates the treacherous landscape of faerie politics, he faces challenges from old foes and new threats alike. His relationships with characters like the enigmatic Maeve and the ever-manipulative Winter Queen deepen, forcing him to confront moral dilemmas. The stakes escalate when he learns that both courts are vying for a powerful artifact, which could spell disaster for the mortal realm.