Although a new version of JumpStart 5th Grade has not been released, this game is no longer listed on Knowledge Adventure's JumpStart website, suggesting it may be retired from the line.
Jo also appears in JumpStart Adventure Challenge, JumpStart SpyMasters: Unmask the Prankster and JumpStart SpyMasters: Max Strikes Back, though she is barely recognizable as the same character in these since she is drawn in a more realistic style and has few, if any, of the personality traits she had in JumpStart 5th Grade.
Jumpstart 5th Grade is set up as a series of missions like most Jumpstart products, but there are a lot fewer missions then in most Jumpstart products (only 6) and rather than playing a separate character, they play a character in the game. In each mission, the games are played in a certain order. Each mission starts with the Hooverville Museum of Art and Geography.
When Jo Hammet was on a field trip with her class, she literally bumped into someone here and he was carried away by a bunch of thugs. However, he left a mysterious pair of glasses behind. Later a talking rat named B. F. Skinny (after B. F. Skinner) shows up with a crossword. The user helps Jo Hammet crack the secret code in this puzzle. The Hooverville Museum of Art and Geography may be named after the Oregon Museum of Science and Industry (OMSI)
It turns out the crossword reveals the address of a place that has been sabotaged. Naturally, the door is locked. The user must solve a math puzzle in order to open it. On the first mission, Martin (the person kidnapped by thugs in the art museum) is chained here. He explains that the glasses can be used to read the minds of the thugs. The user then plays a grammar game where they find the correct word to go into the thugs' dialog. Their thoughts reveal the way to get to the bomb.
It turns out that Jo Hammet needs three items in order to get the bomb. She must visit three different places in town to get them.
The person serving the drinks here is really an undercover reporter named Bernie. Bernie will give Jo Hammet one of the things needed to get to the bomb if the user helps him make drinks for patrons. First the user mixes different juices together. On the second and third levels, the user must also help serve the drinks.
The Boulder Canyon Mine Shaft was closed by the Park Service due to falling rocks. Maggie Mead hasn't any visitors but Jo Hammet since then. Maggie Mead needs three items retrieved from the mineshaft. The further down the user goes, the older the objects are. Maggie needs one object from each layer. The lowest layer has natural artifacts such as dinosaur bones. The middle layer has Native American artifacts. The uppermost layer has artifacts from early America.
Upon the second visit to sabotaged site, Jo Hammet uses the items to get to the bomb without getting hurt. To disable the bomb, the user must play a decimal game where they attempt to make the number in one box equal to the number in the target box using a little android. Naturally, there are some defense androids that try to stop the user. If the user's android runs into one of the defense androids, the bomb is shown to go off, but Jo then appears on the screen and, breaking the fourth wall, informs the user that this can't happen in an educational product and the game resets.
Once the bomb has been successfully disarmed, Jo Hammet returns to the museum and gets a new crossword from B.F. Skinny, and the next mission begins.
The game concludes at Boulder Canyon Dam. Dr. X has blown up the pumping station, raising the water pressure substantially so that when he blows up the dam, the water will destroy the entire city. Jo Hammet then travels to the bomb where the user is supposed to click a small switch near Jo that will move a gate, which will divert the water away from the city. Dr. X, who is only shown in silhouette until that point, is finally seen. Though Jo Hammet saves the city, Dr. X disappears, never to be heard from again.