てんしのかけら the lost article of memory

Memory keeps binding people...
Main character acquires teacher's license, but is unable to find proper job. For half a year he only reads lectures and gives tutor exercises. Finally a vacancy at a municipal girls school in a small town opens up, and protagonist jumps at the opportunity. A silent girl with a mysterious presence, a class representative and a reliable person, an inspiring fast-runner girl, a former classmate to accidentally meet here - they all resemble angels.
Various encounters await main character. The thread of memories will finally be repaired - but in which way?