"Grace Cahill was highly accomplished. She was a talented cartographer, a fearless aviator, and an expert at breaking out of foreign prisons. But her greatest feat was designing a scuba suit for her cat, Saladin. When the Tomas spotted Saladin exploring a sunken ship off the coast of Portugal, they had two questions: 1) What was the cat looking for? and 2) Had Grace Cahill finally lost her mind?"