The Harvest Tide Project by Oisín McGann

Taya and Lorkrin are Myunans - shape-changers who can sculpt their flesh like modelling clay. They accidentally release Shessil Groach, a timid botanist working in captivity on the top-secret Harvest Tide Project. A massive manhunt is launched by the sinister Noranian Empire, which will stop at nothing to protect its Project.With the help of a scent-seller, a barbarian mapmaker and their uncle Emos, the teenagers and Groach keep one step ahead of the Noranians, while they try to find a way to sabotage the Harvest Tide Project and avert the disaster it will unleash.