The set, designed by Louisa Thompson, elicits a kind of amazed admiration before the lights are dimmed. It's absolutely huge, three stories tall, and it arrestingly depicts the big city from a 10-year-old's perspective. It's all apartment halls and anonymous doorways, and throughout the show it moves and shifts to create balconies and a blue-sky rooftop scene. The action onstage is, thankfully, of equally strong quality. At first glance, Melissa James Gibson's play seems to address the rather insubstantial problems of a precocious and cheeky fifth-grader, but soon the subtle script reveals that Sasha has serious problems indeed, including an absent father, the looming threat of academic failure, and an immigrant mother reduced to working as a cleaner after leaving a professorship behind in Russia. Emily Zimmer gives Sasha matter-of-factness with an undertow of vulnerability, in the process nicely avoiding sentimentality. Zimmer works well with Steve Hendrickson, the latter in a wheelchair, breathing from an oxygen tank--very much the semi-scary crank next door with a heart of gold. The dialogue is intelligent and wry from start to finish, and there are unexpected turns, such as when a neighbor played by Susanna Guzmán tells Sasha that some parents aren't really up to the job, and in those cases it's the offspring who have to be smart enough to get their needs met elsewhere. This is a production pitched at older kids capable of tackling such weighty matters--during a show last week, the five-and-under set was executing intricate variations on the Squirmy Worm. Most of the background music is soft acoustic guitar by Barbara Brousal, playing an upstairs neighbor who lives a sort of parallel life to Sasha's. Oh, and CTC wouldn't let you go without a few mind-blowing visuals. In this show there is a series of time-warping effects that culminate in a moment of great beauty and bittersweet contemplation. Brooklyn Bridge affirms the emotional, intellectual, and physical protection of children by the community of adults, which is a fine thing. We're all just passing through, after all. Better to do so as part of something larger than ourselves.