Gear up for a seriously exciting voyage with some friendly rodents in tow. Helena, Louise, Beatrice, and Lamont are mice that live in the Hudson River Valley (in New York) back in the late 1800s. They have a comfy life inside the walls of the Cranston family house, and their days are full of crumb-collecting and coffee drinking (yep, these mice drink coffee). And they also include a fair bit of drama. Like when Lamont's tail gets bitten off by a snake. Ouch, right?
But this sweet mousy life has its sad patches too. You see, Helena's dad was eaten by a cat, and back in the day, her mom and two older sisters drowned in a rain barrel. This means that she really doesn't like animals of the feline persuasion. And she definitely doesn't like water. Actually, she's super scared of it.
Life gets turned upside-down for the Cranston mice when they find out that the Cranston family (whom they call the Upstairs Cranstons) are moving to England. The Cranstons have two daughters—Camilla (the pretty one) and Olive (the awkward one)—and they want to go to England to find Olive a hubby.
Now there's one big thing the mice don't like about this picture: water. You know, that big huge Atlantic Ocean that they'll have to sail across. Helena talks to Aunt Fannie Fenimore, a wise mouse neighbor, and she says that the Cranston mice should take a chance and hop on the ship anyway—it's the only way to keep their family together.
This means it's time for the mice to take a huge leap of faith. They're seriously scared to start their journey across the sea, but on board the ship they find some cool things—like the chance to make new mice friends, including Nigel (the ship's mouse-steward) and the Duchess of Cheddar Gorge (a royal mouse-in-waiting for the human Princess Louise). Yep, there are royal mice on this ship.
So the mice are having a pretty jolly time on this boat, even though Helena sometimes feels left out around her siblings. But when they all go to Princess Louise's party to help the Cranston sisters nab husbands, these mice realize they need to work together. Thanks to their help, Camilla meets the handsome Lord Peter. Way to go, mice, way to go.
Plus, after the party Helena makes a new human friend, little Lord Sandown—she helps him avoid getting spanked by his mean nanny. Helena also discovers that Olive is in love with the ship's doctor. With all this adventure and gossip, Helena sure isn't feeling so left out anymore.
As the ship nears England, three engagements get finalized aboard this boat:
Helena is sad that Beatrice isn't marrying a rich mouse, named Lord Peter, who has a crush on Beatrice, but in the end Helena gets to serve as Maid of Honor in Beatrice's wedding, so that's cool. And since Helena is now assistant mouse-in-waiting to Princess Louise, the wedding is in Buckingham Palace and it's a seriously swanky affair.
And there's an extra silver lining in the end. You know that hunky Lord Peter mouse who first had his eye on Beatrice? Well he asks Helena to dance at the wedding. Looks like she might be in for some romance of her own.