The Treasure Chest Books in Order

At the start of this series, fifth-grade twins Felix and Maisie Robbins are reeling from their parents' divorce. They have to leave Manhattan and move to Newport, Rhode Island, where they end up in the servants' quarters of Elm Medona, a huge old mansion tied to distant relatives and a long, messy family history. The place is full of locked rooms, old stories, and one object that changes everything, a mysterious treasure chest that can send them back in time.

History is the hook.

In Clara Barton: Angel of the Battlefield, the twins' first jump lands them on a Massachusetts farm in 1836. From there, the books send them all over the map, St. Croix with a young Alexander Hamilton, China before the Boxer Rebellion with Pearl Buck, Coney Island with Harry Houdini, a Lakota village with Crazy Horse, Hawaii with the future Queen Liliuokalani, and later Italy, Kansas, London, and Russia. Each trip drops Felix and Maisie into the middle of a real historical moment, but the stories stay brisk and focused on what the twins do once they get there.

What keeps the series from feeling like a simple history tour is the mystery waiting for them back at Elm Medona. The Pickworth family has missing relatives, stolen artifacts, and more than a few secrets about how the Treasure Chest works. The disappearance of Great-Uncle Thorne hangs over the early books, and when he finally starts taking up more space in the story, life at the mansion gets even stranger. Later books widen the arc again with the search for Amy Pickworth, another family figure whose fate matters to the twins.

The family mystery keeps the series moving.

Felix and Maisie are a good pair for this kind of adventure because they do not react the same way to anything. They bicker, worry, hide things from each other, and then team up when it counts. The action is fun, but the books also keep returning to the ordinary things that feel huge when you are a kid, missing your old home, figuring out what divorce changes, meeting a parent's new partner, and deciding who in your family can really be trusted.

The overall tone is adventurous, accessible, and lightly spooky rather than dark. There are chases, separations, clues, and cliffhangers, but the series also has a warm curiosity about the past. If you want middle grade time travel with a strong sibling dynamic, a memorable setting, and lots of real historical figures worked into the action, The Treasure Chest has a lot to offer. Each book also includes short nonfiction material on the featured figure, which fits the series well. You get the fun of the adventure, then a chance to learn a little more once the dust settles.