While wrapping up a kidnapping case, Conan and Harley find themselves on the trail of another criminal: a serial arsonist who leaves a model of a red horse at the scene of each fire. The police and fire departments are stumped, but to Conan, the case feels eerily familiar. Can he jog his memory before the arsonist claims another victim? And what will he and Harley do when Rachel and Kazuha receive the fatal red horse?