Young and penniless medical student Edward Eden is approached by old and wealthy Egbert Elvesham, who doesn't have an heir and is looking for somebody to inherits his fortune, provided they take his name.
Mediocre artist Alec Harringay is trying to depict St. Catherine for a submission to the Royal Academy but he is never satisfied with his work.
This event radically transforms Harringay, who eventually kills his wife Isabel and suffer the consequences.
When Pawkins dies, Hapley loses interest in his research, and shortly after he is haunted by a moth with the face of his old enemy.
However, they are revealed to be hallucinogenic: after an overdose, he starts consuming a calibrated amount to improve his humour in daily life.