When Lexi and her younger brother Jimmy miss their beloved Grandma, their questions feel heavier than usual, especially all the "whys." Why does life change? Why do things we love feel different? Why does love still matter? Then Grandma's final letter arrives, inviting them on a treasure hunt she planned just for them. Guided by Grandma's handwritten notes and Bible verses, Lexi and Jimmy follow clues through familiar places filled with memories, including lamps, birdhouses, flowers, and keepsakes. With each discovery, they uncover reminders of Grandma's love and gentle truths about what lasts, what guides us, and what truly has value. As the hunt unfolds, the children begin to see that asking "why" is not something to rush past. It is how we learn what matters most. The final treasure leads them to Grandma's Bible and Jesus' answer to life's biggest questions. The Biggest Why is a tender, hope-filled picture book that helps children explore curiosity, change, and faith in an age-appropriate, comforting way. Rooted in Scripture and supported by warm, expressive illustrations, the story invites thoughtful reflection without overwhelming young readers. Ideal for families, classrooms, libraries, and churches, this book includes discussion prompts that support meaningful conversations between children and caregivers. Recommended for ages 5-8, The Biggest Why works well as a read-aloud for younger listeners and as an independent or supported read for early elementary readers.