The heroine this time is Makoto, a pretty average, if not well-endowed girl. The story starts with her getting confessed to during a sunset. She accepts the confession, but things don’t progress past a kiss that evening. Her newly appointed boyfriend walks her home, where we’re shown her adoptive brother looking at them from his window with an evil grin. 
 
(Source: Fakku!) 
 
Note: A demo was available to the players of RPG browser game Aku no Onna Kanbu: Perigee New Moon (悪の女幹部ペリジーニュームーン) on May 6, 2021.

Mako-chan Kaihatsu Nikki