A vacant building is a melancholy sight, like a darkened theater or a diner sitting alone at a table set for two. The atmosphere is especially unsettled on West 127th Street in Harlem, where an office building called Malt House has grown — magically, you might think — from the husk of a 19th-century brewery. Walk in, and you’re standing in the pause between tales that have been erased and others yet to come. And because parts of it appear ruined and others gleam, it’s a freeze-frame in a film that could run in either direction; you can’t always tell the difference between incompleteness and decay.