Everyone knows kids make hardened adults all soft and mushy — even Bill Murray. In “St. Vincent,” Murray plays Melissa McCarthy’s grumpy, debt-laden neighbor, Vincent, who agrees to look after her 12-year-old son (Jaeden Lieberher) for $11 an hour. Of course, Vincent isn’t an ideal babysitter. His technique includes taking Oliver to the bar and the race track. Along the way, he introduces the young boy to a “lady of the night,” played by Naomi Watts. All that madness leads to lots of growing up and realizing that life is great, but fortunately the trailer doesn’t veer too heavily into the syrupy kid-teaches-curmudgeon-how-to-live motif.

This fall is packed with promising dramedies (“The Skeleton Twins,” “This Is Where I Leave You,” something Cameron Crowe has yet to assign a title to), and “St. Vincent” looks like it squares nicely with those. Chris O’Dowd co-stars as Oliver’s Catholic school teacher. The movie opens Oct. 24.