In <i>Muv-Luv Alternative</i>, Takeru wakes up three years after the end of <i>Muv-Luv Unlimited</i> to find himself back in his room. Although he first thinks that everything that had happened to him was a dream, he soon feels that something is wrong, and leaves the house to find that he has been sent back in time to the beginning of the events in <i>Unlimited</i>. Unwilling to accept something like Alternative V, he decides to help professor Kouzuki to complete Alternative IV and save mankind.
(Source: Wikipedia)