When classic car restorers Billy and Ollie Ashcombe take on a vintage coupe with a mysterious past, they expect rust and loose bolts—not buried government secrets and experimental technology decades ahead of its time.Hidden beneath the polished chrome and perfect lines is VerdEx R4: an adaptive engine system that doesn't just respond to its driver—it learns, corrects, and sometimes refuses. As the siblings delve into the coupe's origins, they uncover a conspiracy of silence, industrial espionage, and a machine so advanced it scared its creators into erasing it.Now, powerful forces want to reclaim it. Others want it destroyed. But the Ashcombes are determined to let the car speak for itself—before it disappears again.Smart, sharp, and driven by mystery and mechanics, The Engine That Shouldn't Run is a high-octane cosy thriller for readers who believe the past never really stalls—it just waits to be restarted.