The friendship between five-year-olds Sara Miller and Judy Levine begins in the summer of 1941, when their families move into adjoining row houses in Washington, D.C. Almost immediately, the United States enters World War II, and their childhood is thrust into a world dominated by the consequences of history. When asked to help their sick friend, Su Ling, keep up with her studies as she recuperates from rheumatic fever, her grandmother, An Lei, teaches them the ancient Chinese game of Mahjong, destined to become an invariable part of their lives as it merges cultures, love, and friendship.

Separated for the first time when they enter college, their personal choices, shaped and impacted by half a century of unparalleled wars, loss, and heartbreak, only bring them closer together, as they marry, raise their families, and pursue their chosen careers. Their lifelong journey, caught in a web of intricate and surprising twists of fate, surfaces in the public eye when a Ukrainian farm girl inadvertently unlocks a thirty-five-year mystery that has haunted them since their graduation from high school.

From coast to coast and across the globe, their heartwarming and compelling story confirms the powerful bond of friendship.