Nobody likes Anderson (apart from me, it seems), and in fanfics he's very often portrayed as a villain and monster, even though Sally was much more unpleasant and offensive.

I would like a story where Anderson stumbles upon an old, cold case and something just clicks. He starts his own investigation (maybe Met isn't officially interested, so he's alone in it). I'd love it to be a proper adventure (maybe a dangerous one, involving dangerous people and maybe he even has to infiltrate a dangerous organisation) with him using his professional skills and, eventually, solving the case and impressing his colleagues, including Greg.

Please, no Philip/Sally. Gen is preferable.