“This book made me think about my own life.” That’s the whole point of literature, according to the morbidly obese protagonist of this exemplary drama by Samuel D Hunter. Charlie is an online English teacher, and that sentence, which he cherishes, appeared in a student essay about Moby-Dick, whose other title is The Whale. Parallels are implied between the suicidal impulses of Captain Ahab and Charlie, eating himself to death following the loss of a lover. The play is partly a pinpoint character study, turning on a superb performance by Shuler Hensley. Beached on the sofa in his cramped Idaho home, he squeezes all his humanity into his sweating, kindly, humorous, agonised face. Around him circle Liz, his friend and nurse (Ruth Gemmell); his toxic daughter Ellie (Rosie Sheehy); and a well-meaning Mormon (Oscar Batterham). All are excellent, but the plaudits go to Hensley — and to Hunter for creating this utterly plausible parable. It will make you think about your own life.