This low-key oddity has the potential for some proper horsepower given the odd but intriguing casting of Peter Dinklage and Shirley MacLaine, but it never manages to build up much comic or dramatic speed – much like Dinklage’s electric scooter, his main mode of transport throughout. The film feels ill-considered somehow, like one of the half-sketched fantasies that Dinklage’s protagonist, a university lecturer named Phil, often indulges in, such as imagining a pair of identical twins (Rebecca Olson) are his sister wives ready to minister to his every need. There’s a reason why it’s best not to know other people’s dreams.

Phil’s other big desire is to own a proper home instead of the shabby condo he rents near the lesser-level Massachusetts college where he teaches cultural economics. One day Phil finds a deal that looks too good to be true. If he buys a granny flat inside the sprawling mansion occupied by eccentric widow Astrid (Shirley MacLaine on sparky form) as a live-in, he will inherit the full $5m spread when she dies. Advised to go for it his by his greasy friend/realtor Dell (Matt Dillon), Phil scrapes together every bit of cash he can and moves in. There are a number of baffling strings attached, of course, including hangers-on who may or may not be Astrid’s children; one of whom, Maggie (Kimberly Quinn), is a lawyer specialising in probate, so she’s naturally keeping a close eye on things. Nevertheless, like nearly every woman in the film, she eventually falls into bed with him, unable to resist that rumbling voice and languid charisma.

The script is by Theodore Melfi, who wrote and directed the similarly languid St Vincent with Bill Murray, and an air of disappointed masculinity resonates in both films; they are easy to consume but don’t give back much, like the protagonists themselves.

• American Dreamer is on digital platforms from 17 March.