Whether conjuring a persuasive Russian ballet onstage without a toeshoe in sight, a functioning locker-room shower minus water, or a Hitchcock-worthy avian frenzy sans feathers, director Shirley Serotsky is clearly having so much fun with the visuals in Adam Bock’s Five Flights that it seems almost churlish to note that the comedy she’s illustrating is cartoonishly slight. A tale of siblings who disagree about what to do with a deteriorating aviary their loving dad built to house their dying mom’s soul, the play substitutes anecdotes and character arcs for plot. But oh, the imagery. At evening’s outset, sweetly ingratiating Ed (Eric M. Messner) walks through a latticework of birch branches holding what looks to be a set-model for a much bigger stage. “Here,” he says, pointing to a glass-enclosed, gazebo-like birdhouse on the model, “is the landscape of this story.” At which point you realize the broken windowpanes behind him mean you’re inside the gazebo with him. Then, with designer Klyph Stanford whisking that latticework of branches this way and that, we’re plunged into a brisk if slightly scattered argument over what to do with the crumbling edifice. Ed’s sister Adele (Helen Pafumi) wants to let a preacher (Adele Robey) appropriate it for her bird-worshipping Church of the Fifth Day (named for the day on which God created creatures of the air). Their tightly wound sister-in-law (Kathleen Akerley) argues shrilly for tearing it down and building a housing development. Noncommittal Ed mutters that he’d just as soon let the place rot, but his outlook brightens when a handsome gay hockey player (Danny Gavigan) stops by and starts chattering away about how hockey is like 19th-century ballet. By the time the hockey player’s whisking Ed, Adele, and an amiably dim bulb of a hetero teammate (Christopher Herring) from a Church of the Fifth Day Bake Sale (where Rice Krispie treats come in the shape of birds) to a ballet (where spectacle gets reflected in the eyes and postures of the viewers), you’ll have gathered that the playwright has the attention span of a hummingbird. But if his script flits hither and yon in search of comic moments, it is ever graceful about the fragility of characters who are feeling their way carefully past loss. Serotsky and her cast make sure you register their progress, even when they don’t. “I only have a few weapons,” Ed tells the hockey player near the end of the evening, “sweetness, politeness; my strongest weapon is not caring.” And even as the words spill from him with a convincing flatness, you look at his eyes, and they give him away.