Inspector Brackenreid believes he can handle serious crime alone while Murdoch is on honeymoon, but Crabtree and three fellow constables he gave leave bought a -then still novel- car together, which turns out the murder weapon of a hit and run or rather the previous, actually lethal poisoning by exhaust carbon-monoxide. The trio's car partakes undercover in the race next day with the suspect trio of car owners whose mate Diderik Haan's widow sold his for only §50 to Crabtree's trio to spite the philanderer. Murdoch and Ogden find their reserved bridal suite in a Manhattan hotel taken by a mystery guest, as turns out no other then president Roosevelt and his security team and, having received by accident a coded message, remain vigilant, despite uncooperative hotel staff, to catch up on an elaborately prepared attempt on the president's life.
—KGF Vissers