Watch Only Murders in the Building Season 3 Online Free. Season three finds Charles, Oliver & Mabel investigating a murder behind the scenes of a Broadway show. Ben Glenroy is a Hollywood action star whose Broadway debut is cut short by his untimely death. Aided by co-star Loretta Durkin, our trio embarks on their toughest case yet, all while director Oliver desperately attempts to put his show back together. Curtain up!