Med student Martin Arrowsmith's (Ronald Colman) future is so bright it's blinding, but his trajectory is waylaid after he marries Leora Tozer (Helen Hayes) and settles down in a quiet Minnesota town. He gets another shot at greatness, however, when he's convinced by an old mentor (A.E. Anson) and a researcher (Richard Bennett) to take on a research project in the West Indies, where a beautiful stranger (Myrna Loy) complicates his life.