Under St. Mark’s Theatre looks like a Eurotrash sex dungeon. Not that that’s a particularly bad thing, but I didn’t expect it to house one of the sweetest shows I’ve seen since “Peter and The Starcatcher.” In the first scene, a gruff, drunk (and preposterously attractive) homeless man gives a frantic dancer his jar of coins so she can make it to a competition on time. From this small act of kindness, a ripple effect touches a whole host of characters, from a Cabbie, to a Guverian Bank Robber (Marlies B. Bell), to a pair of anxious actors auditioning for a Lars Von Trier movie.

Written, directed, and (somewhat) starring Yael Grinberg, she’s crafted a play that speaks to her natural talent for comedy and the angels of our better natures. With a cast as diverse as the city itself, Grinberg’s work is fresh and vivifying; not to mention a funky snapshot of millennial hope, delusion, and neuroticism.

It’s far from a perfect show. There’s an unrehearsed quality to the production, actors fumbling with lines and little nuance to speak of. Also, the script has several detours from logic (why the hell did a Bank Robber capture and drag a guy outside the bank?) But “How To Save a World” succeeds in what it sets out to do. Be kind. Be thoughtful. Be fun.

Follow your dreams. Be good to each other. A lovely sentiment and one I wouldn’t expect in a theatre scene that only serves hope with an equal dose of nihilism. Such a simple message, it’s a shame we haven’t learned it yet. Grinberg has, and I look forward to seeing what she accomplishes in the future.