In this glorious small-scale show, La Costa Theatre Company exhibits the same energy and classy confidence it brought to The Last Five Years earlier this year. A New Brain–William Finn and James Lapine’s 1998 musical about Finn facing brain surgery–employs 34 songs in 90 minutes to chronicle fears of mortality and doubts about art. Directors Greg Malen and Betsy Hansfield put a flawless cast through all the right moves and notes. Though Jonathan Hymen and Riley Thomas are too young to play midlife lovers struggling with a near-death experience, they’ve clearly grown into their parts. And the musical direction, by Thomas and Erika Brett Holleb, is so good it’s scary. Through 8/27: Thu-Sat 8 PM, Sun 4 PM, A Red Orchid Theatre, 1531 N. Wells, 866-468-3401, $15-$25.