1942. New Zealand is under threat of a Japanese invasion. Louise MacGregor, formidable scientist, is sent in search of Pterocladia Lucida, a simple seaweed to aid the war effort. May Smith, an untried youngster, is plucked to assist the prickly botanist as a sketch artist. But having only recently discovered her Māori heritage, May has other questions and struggles to meet Louise's rigorous demands. The imagined natural world, alongside Māori cosmology, provides a lush environmental immersion into the lives of two women who learn to help each other grow in a time when expressing feelings of unbearable sadness was forbidden for the good of all. Three additional characters.