Grinstead was an art collector.
When he was around 23 years old, Grinstead was working for Bertrand Garnier, an art dealer. He was sent to Skipton's studio and it was here that he met Marisa van Zee, who was sitting for a portrait. As soon as he saw her, he knew she was from another world. The two were lovers for less than a month.
Later life and death
Grinstead went to visit Horley at the latter's college in Oxford. The two talked about the portrait, which Horley had recently bought, and the bronze monkey which seemed to follow it. When he saw the picture, Grinstead told Horley what he knew about Marisa. After getting more and more ill throughout the night, Horley became unable to breathe.
Grinstead left on the premise that he was going to call for an ambulance, but instead smoked a cigarette at the bottom of the stairs waiting for Horley to die. He returned to Horley's room and took the portrait, leaving the monkey because he assumed it would follow him. As he stepped out onto the High Street, Grinstead was hit by a taxi and died.