Mr. Mercedes is a gripping crime novel by Stephen King, the inaugural book in the Bill Hodges trilogy. It plunges readers into the world of retired detective Bill Hodges, who is drawn back into action by Brady Hartsfield, a psychopathic killer known as 'Mr. Mercedes' for deliberately plowing a stolen car into a crowd. Hodges, battling his own demons of depression and purposelessness in retirement, finds a renewed sense of mission in his cat-and-mouse game with Hartsfield, who taunts him relentlessly. The novel delves into themes of obsession, mental illness, and the timeless struggle between good and evil, offering a chilling and suspenseful read.