After their superb work on the Island of Sodor back in November, the Mane 5 (and Misty) are invited back to Sodor to help out. Construction work on a new quarry and rail line has led to dramatically increased traffic, but mysterious events, an oddly unsympathetic controller, and numerous other problems conspire to through the Island into chaos. Can our heroes discover the truth about the Secrets of Sodor before the island descends into pandemonium?

Based on the 2015 Thomas and Friends special Legend of the Lost Treasure, and incorparating the plot of the 6th Chapter of Make your Mark as well as the Make your Mark special Secrets of Starlight. Written as part of the 40 years of Thomas and Friends celebrations, and the grand finale of the Opaline arc of the FalmouthVerse.