An unusual murder brings together three strangers - John, Jack, and Charles - on a rainy night in London during the first World War. An eccentric little man called Bert tells the three men that they are now the Caretakers of the Imaginarium Geographica, an atlas of all the lands that have ever existed in myth or legend, fable or faerie tale. These lands, called the Archipelago of Dreams, can be traveled to in Bert's Dragonship, the Indigo Dragon (captained by Bert's young, beautiful, smart, brave, and witty daughter Aven), one of only seven vessels able to cross the Frontier between our world - the Summer Country - and the Archipelago. Pursued by terrifying, inhuman creatures desperate to get their hands on the Imaginarium, they flee London with Bert and Aven in the Indigo Dragon, travelling to the Archipelago - a place where they meet the very people and creatures who not only inspired the greatest fantastical tales of all time, but the ones who would go on to inspire their own tales when they grow up to become JRR Tolkien, CS Lewis, and Charles Williams.

And thus begins The Chronicles of the Imaginarium Geographica.

From the very real Caretakers to the creatures who assist them on their adventures in the Archipelago - the characters who appear and make a difference in The Chronicles of the Imaginarium Geographica.