In Twinless, two young men meet in a twin support group and form an unlikely friendship. Roman (Dylan O’Brien) and Dennis (James Sweeney) both search for solace and an identity without their other halves and soon become inseparable outside the group. But when Roman meets Dennis’ ebullient co-worker, Marcie (Aisling Franciosi), all is revealed to be not what it seems, as each man harbors secrets that could unravel everything.