Shark Heart tells the poignant tale of Lewis and Wren, whose first year of marriage is also destined to be their last. Just weeks after their wedding, Lewis is diagnosed with a rare condition: while he will retain his consciousness, memories, and intellect, his body will gradually transform into a great white shark.

As Lewis begins to exhibit the features and impulses of one of the ocean's most predatory creatures, his complex artist’s heart grapples with unfulfilled dreams. Can he find peace within this new reality?

Initially, Wren struggles internally with her husband’s fate. Is there a future for them after Lewis's transformation? Her journey is further complicated by the surfacing of long-repressed memories, which take her back to her childhood on a houseboat in Oklahoma, her college years with an ex-girlfriend, and her unique friendship with a woman expecting twin birds.