The fourth book about Curious George and his anthrapoid antics concerns the mysterious letter which came for him. George couldn't read, but maybe he could write a reply. In the attempt he spilled ink on the floor. Then a box of soap flakes poured into the ink to clean it produced tons of bluish lather. Borrowing a pump George caused havoc at a farm and a zoo. But he redeemed himself before the finale by proving himself a champ chimp when he realized that the letter was from a scientist asking George to become the first space monkey. George complies and wins a medal.