Uki and the Swamp Spirit (Longburrow #5)

Uki had the sensation of a sickly green light, spreading out through the networks of water. Of tendrils connecting all the creatures of the marsh in a web . . . Linking itself so it could poison it all and destroy it.
Uki and his friends have two more spirits to find and capture. After defeating Valkus, they make for Clarice, who is spreading disease through the swamps. Can Uki and his friends outwit him - all whilst they themselves are being chased by the Endwatch and Jori's clan of assassins?