A mother secretly believes she's raising the wrong son, mistakenly switched at birth. But secrets unravel in a gripping and affecting novel about parental love, impossible choices, and what it means to truly be there for someone.For fourteen years, teacher Elsa Vargas has hidden her belief that she's mothering the wrong child, accidentally switched at birth. Her beloved son Bird is not like the rest of the family. He's the introvert among extroverts, the optimist among skeptics. But Elsa knows love is more important than truth, and the best way to keep Bird is to leave well enough alone.Then the odds catch up with her. A student named Thomas in Elsa's math class is suddenly uncannily familiar, an older version of Bird's little brother. When she realizes Thomas shares a birthday with Bird, Elsa has a terrible realization: Thomas is probably her long-lost son.Soon Elsa is on a clumsy journey to get to know Thomas--and to confirm the truth. Testing the bonds of family, friendship, and even community will surely all be worth it if she gains a son. But what if she loses Bird, the boy she has loved and mothered since his first days of life?