How do you make a hug between grandmother and grandson a high point of a play without making it corny or sentimental? That's the trick playwright Amy Herzog and director Mark Rucker pull off in the compelling drama 4000 Miles now at American Conservatory Theater's Geary Theater.

The moment comes fairly early in this 90-minute one-act after 21-year-old Leo (Reggie Gowland) has surprised his 91-year-old grandmother, Vera (Susan Blommaert) by showing up in the middle of the night after completing a cross-country bicycle trip from Seattle to Manhattan.