CO2

Year 30XX AD.
Humans colonize space and genetically create many new life forms. Towns with forests and clean air are covered with domes due to heavy environment pollution.
Main heroine is a student who is going to home town for summer vacations. But school main computer breaks down, and as a result barrier with the outside world is going to vanish in three days. Only two more students stay at this time at school. Will they succeed in preventing the disaster in three days time?

[From vndbreview]