The fourth and final book in Mishima's landmark tetralogy, The Sea of Fertility The dramatic climax of The Sea of Fertility tetraology takes place in the late 1960s. Honda, now an aged and wealthy man, discovers and adopts a sixteen-year-old orphan, Toru, as his heir, identifying him with the tragic protagonists of the three previous novels, each of whom died at the age of twenty. Honda raises and educates the boy, yet watches him, waiting.