Cave Story Prequel: Query's Quest
Professor Shift, the man who would go on to develop the robots Quote and Curly Brace, with the help of his wife Doctor Enter (called Doctor Return in some translations), has just finished his first prototype robot, Query.
You play as Query, going through various battle-related tests designed by Professor Shift to determine if you can make it past the prototype stages.
However, halfway through the tests, Professor Shift stumbles upon the idea of a connection system between two robots, and has been developing a new AI which would be incompatible with Query's hardware. Even though Query has been passing the tests with flying colors, he isn't quite what Professor Shift is looking for.
Query is then assigned to gather various parts and materials to help Professor Shift develop a pair of combat robots, as well as defend the lab against attackers who want to get their hands on the new technology.
As Quote and Curly get closer to completion, the military approaches Professor Shift and requests permission to mass produce his robots and create a "defensive army", with the hidden intention of acquiring a powerful artifact hidden deep within a floating island. Professor Shift refuses, but a secret agent manages to kidnap Query so that the military can create their army. After production starts, Query manages to break out of captivity and makes his way back to Professor Shift's lab, only to find that the place has been ransacked and everything appears to be missing except for a single computer. Query plugs in to recharge, and a message begins to play on the computer: a distress signal from Professor Shift. He and Doctor Enter have escaped with the nearly finished Quote and Curly, but are being pursued by an unknown enemy and need Query to save them. Query rushes to their aid, but on the way he runs into their pursuer. An epic battle ensues, and both he and the enemy find themselves on the verge of death. The enemy gets back onto his feet and hobbles over to Query, who is completely immobilized. As he prepares to strike the final blow, Query receives a message from Professor Shift, stating that Quote and Curly have been finished thanks to Query having held off the enemy and that his purpose has been fulfilled. As the enemy smashes his fist into Query's chest, hoping to finish him off, Query short-circuits his own battery and ends up electrocuting his foe and they both perish.