After Thomas and Percy get spooked by a suspicious rumbling, the engines set off to figure out the secrets of the old mine inside Lookout Mountain. Will Bhaneja, Meesha Contreras, Glee Dango, Bruce Dow, Talia Evans, Kayla Lorette, Joe Pingue, Dana Puddicombe, Ava Ro, Chuck Smith, Jenna Warren, Jamie Watson, Charlie Zeltzer Added on Netflix 2023-04-01.