The Melissa & Doug On the Go Secret Decoder Deluxe Activity Set gives kids a chance to crack codes, uncover hidden clues, reveal secret messages, and be super sleuths. ACTIVITIES GALORE: 50+ activities include a Secret Decoder Game Book, Seek & Find Game Book, Secret Message Activity Pad, and magic-reveal sticker sheets. PLAY AND LEARN: This robust activity set encourages problem solving and critical thinking.