Starting "801 Media vs June" sounds like a good idea, I think especially if we can all keep it focused on more general themes and esp. the future releases, as those are not really covered elsewhere. Feel free to open it.
Re: "synopsis" of this series (spoiler-free) - it's certainly a josei (IMO) title, with deep, psychological development of characters and their interactions. It's probably one of the two-or three manga series with most developed characters I ever read. It even beats another (highly recommended) series by this manga-ka,
After School Nightmare (ASN) (the latter is often classified shojo/gender-bender with some shojo-ai / shounen-ai elements).
Cornered Mouse depicts the relationship between two men in a plausible (to me), realistic fashion. It's not tragic, but we witness all the ups and downs of real life / relationship, you won't find "sugar coating" (or another extreme, dramatic uncalled-for suicides or such) in this manga. It was really hard for me to stop reading once I started it, the manga was one of the most addictive, emotional and enjoyable reads for me as of recent, alongside with ASN by the same author.
Art in
Cornered Mouse is also fantastic, more refined than in ASN or X-Kai / other works of this manga-ka I'm familiar with. (Or maybe because highly eroticly charged explicit sex scenes made such an impression on me?

Well, even well beyond sex scenes, the artwork, IMO, is gorgeous).
Seeing that it's unlikely our shores will see
Cornered Mouse any time soon, I suggest reading
After School Nightmare (sorry, it's not really a June title, but once we're on the topic..), which is translated / published in the US - ASN though being not directly comparable to
Cornered Mouse can give you some idea of the depth and strength of character development / plot this manga-ka is so famous for.
P.S. / As a disclosure, I own and read German and French editions of this manga, and no, my review/opinion above has nothing to do with perusal of scans and such.