Only the Sound, Chicago Dramatists. Jenny Laird’s sweet, simple, sometimes quite touching story explores the scars left when children are forced to become caregivers. Nat (Aaron Snook), a 16-year-old bird lover in North Carolina, assumes primary responsibility for his mother, who has multiple sclerosis, when his alcoholic father fades from the scene. We also see the grown-up Nat–now called Nathan–working at a bird sanctuary, wrestling with his own MS, and being torn between his wife’s nearly militant desire to have a baby and his own uncertainty that he can raise a child given his flagging health.

There isn’t anything incredibly vital or fresh in Laird’s story, but under Russ Tutterow’s direction the strong cast manages to conjure up an air of wistful truth. Tim P. Miller brings a crusty ruefulness to grown-up Nathan, and the scene in which he first meets his motormouthed, painfully self-aware wife (a terrific Julia Neary) is a flat-out comic gem. Janelle Snow as Nat’s volatile mother takes a while to warm up, part of the problem being a lack of chemistry with the mannered Richard Marlatt in the thankless role of her philandering, self-pitying husband.

At times Laird’s overworked metaphors–birds, flowers, and Shakespeare all do a lot of heavy lifting–threaten to overwhelm the show. But her intelligence and compassion for her characters keep it from sinking into the bogs of self-indulgence.