It is unclear how or why he returned to D'ni while Yeesha was living alone in the cavern, but she discovered him in the Ae'gura Library one day. Clearly a Writer well-trained in the Art, he and Yeesha argued heavily on its use, as his training clashed strongly with Yeesha's creative approach. In time they started to cooperate and learn from each other, much as Atrus and Catherine did. Calam was said by Yeesha to have known all the D'ni knew about the Art at their fall and to have been a "Master", a "D'ni Writer of Ages", which may imply that he had been a Guild Master in the Guild of Writers. Eventually they trusted each other and became close friends. After learning of the bahro and the Tablet together, Yeesha believed the he would become the Grower one day.
Calam was murdered by an unknown person, whom Yeesha "destroyed ... in a fit of rage". Yeesha seems to blame herself for Calam's death, but the reasons for this are unknown.