JumpStart 2nd Grade Readers: CJ and the Mysterious Map is a JumpStart book in the Readers series published in 2000.
On the morning of CJ's birthday, CJ and Edison are both at Frog Manor. CJ laments that it won't be the perfect birthday if he doesn't get to go on an adventure. Just then, the doorbell rings, and a mailman delivers CJ an envelope. The envelope turns out to contain part of a map, and a letter saying that the map will lead to great treasure, but only the bravest will succeed. Edison seems skeptical of the map's legitimacy and tries to talk CJ out of following it, but CJ is too excited to listen and quickly packs up for an adventure. As the two set off, the identity of the mailman who delivered the letter is revealed to be none other than CJ's nemesis Dr. Listick in disguise, who intends to find the treasure before they do.
The first place that the map leads CJ and Edison to is Egypt. They arrive at a large tomb, and proceed to make their way through it. They encounter Dr. Listick in the tomb, who tries to trap them by blocking their path with a large boulder. CJ escapes by scaling a wall using Edison's light as a guide. As they make their way out, CJ spots a wall carving that shows where they need to go next: Atlantis. CJ and Edison get to Atlantis in a submarine, when once again, Dr. Listick shows up in a submarine of his own to thwart them. CJ maneuvers his sub over towards a group of seahorses to make them scatter, which creates a bunch of bubbles that obscure Dr. Listick's view of them just long enough for them to escape. Then CJ and Edison see a message on some seashells that spells out the last location they need to visit: Machu Picchu.
By the time CJ and Edison reach Machu Picchu, it is already sunset. At the bottom of a mountain, CJ spots a carving on a stone that tells them that the treasure is located in a cave east of the ruins, but to watch out for precarious rocks that could fall at any time. CJ and Edison start making their way through the ruins, when Dr. Listick appears behind them, and speaks in a loud voice so as to disturb the delicate rocks. As the walls around them begin to crumble, CJ and Edison rush out of the ruins and into the cave, with Dr. Listick still on their trail.
CJ and Edison go deeper and deeper inside of the cave. Suddenly, CJ is greeted with a surprise party by several of his friends. Dr. Listick, realizing that the treasure was actually CJ's party, is dumbfounded and storms out of the cave. Meanwhile, CJ hugs each of his friends and thanks them for the party. Then he wonders who planned it all for him. All eyes turn to Edison, who bashfully admits that he did, not wanting CJ to be sad on his birthday. CJ proclaims that Edison is the best friend he could ask for, and Edison agrees to it, and then wonders what he'll get for CJ's next birthday.
- This book is partially inspired by the game JumpStart Reading for Second Graders. It features the main villain from the game, Dr. Listick, as well as several key locations from the game (Machu Picchu, Egypt, and Atlantis).