[1][2][3] The book series is about a young boy named Charlie Ashanti, who is of Ghanaian and British heritage, and who can speak the language of cats, after accidentally swapping blood with a leopard cub.

Charlie is on the run on a floating circus, with six lions in tow, aiming to return them to the wild of Morocco and to rescue his parents who have been kidnapped by a sinister corporation known as the Corporacy.

The world has been changed by global warming and other environmental influences; the most notable example is the ruin of Venice, which is now half sunken under rising waters, and otherwise decayed from pollution.

Charlie is a young child who is able to speak to cats (and all felines) due to an incident involving a leopard cub's blood when he was a baby.

Charlie, closely avoiding being kidnapped himself, sets out to find them and ends up on board Circe, a circus ship making its way to Paris.

They make their way to Gare d'Austerlitz where they hide on the Orient Express which is destined for Venice, the place Charlie's parents are rumored to have been taken.

Charlie and the lions reach Venice and seek refuge at the Palazzo Bulgaria, the King himself travelling onwards and leaving the runaways in the trust of his right-hand man Edward.

After only a few blissful days reunited with his parents, Charlie is captured by the revenge-seeking Maccomo, who puts him on a ship and takes him (along with Rafi) to the Corporacy headquarters on the island of San Antonio near Haiti.