 Mr. Conductor s supply of magic gold dust, which allows him to travel between Shining Time and Thomas s island, is critically low. Unfortunately, he doesn t know how to get more. Meanwhile, Thomas is fending off attacks by the nasty diesel engines. Getting more gold dust will require help from Mr. C s slacker cousin, his new friend Lilly, and her morose grandfather, plus the secret engine he s hidden all these years and couldn t get running.