Spoiler here

I kind of agree to that, the story involves how Jessie randomly flies in as a ninja star being able to transform herself. Agata escapes as she was about to be found out by the hero. And during that Jessie goes balls to the wall with the hero. But next story arc Jessie goes around collecting information helping you to progress the story, and she kind of dissapears suddenly. Solveig who was also part of the laboratory as being a toy, if not mistaken. She wants to help you, but as you progress near the end you notice it's all a misunderstanding for Jennie and she was about to get married and fucked by the man she actually liked. And somehow you get her as harem girl without her agreeing. During the upgrade scene you get Jennie and Jessie but it's mostly focused on Jennie. I think it would be much better if they turned the reward "Jennie" into "Jessie&Jennie" as duo basically, not separated.