In the Künzinger Museum, Quintana, a perfectly healthy woman, allegedly dies of heart failure. Shortly thereafter, the self-proclaimed investigators Thekla, Hilde, and Wally stumble upon a second corpse - stabbed with a Roman spearhead. The trail leads to a perpetrator who shouldn't actually exist: Are they perhaps chasing a phantom? Relentlessly, they get closer to the answer - but unfortunately, they also find themselves in life-threatening danger.