Mary and Tom are parentless Irish siblings who arrive in New York City via ocean liner in 1886 and quickly find themselves on a wild, cross-country journey aboard a transcontinental "Orphan Train" where they meet an extraordinary new friend who will change their lives forever.
Tad dreams of becoming an archaeologist traveling the world, uncovering hidden secrets and lost treasure, but his job working construction keeps him daydreaming instead of exploring. The chance of a lifetime comes when he is invited to attend archaeologist Sara Lavrof's presentation of her latest discovery - the papyrus that proves the existence of the Necklace of Midas, the legendary King who turned everything he touched into solid gold.