It seems to me that Kodaka Kazuma looked at the yaoi fan community which has arisen around the 90s anime/manga/drama CD series Weiss Kreus, and decided to just go ahead and rewrite it as an actual yaoi. The plot revolves around four young men who investigate crimes which the police cannot touch, instructed by a disembodied and anonymous voice who contacts them over a computer connection. There's the impossibly genki young computer specialist Kippei (Omi), the buff, sporty Sogo (Ken), tall and overtly sexy hairdresser Tamaki (Yohji), and the detective agency president and ex-military man Yamato (Ran). There's also a police detective, Makita, interested in finding out who these vigilantes are.
The first volume comprises two chapters of investigation showing how the team use different identities to solve cases, a long section of deliciously angsty backstory for Yamoto, and to conclude, two shorts also about Yamoto's backstory.
Overall this is a definite cut above most yaoi. There's a plot, and actual character development. The art shows a strong competant hand, which works with the dialog to always make the action clear. There were no translation or editing problems. There isn't much sex; one teaser scene on the first page and 11 non-explicit pages in the backstory chapter. All the sex is consensual and affectionate.
I found it really refreshing to read, and although it definitely stands alone I see this book more as a set-up for future volumes. The interaction between the four main characters has lots of potential, and no doubt in future volumes we will learn more about who is pulling the strings.
EDIT 12/7/11: I thought I might clarify a few points as ai_chan1 and I seem to have differing ideas about the sex scenes; I described it as not explicit, and ai_chan says it has graphic sex. So, to me, graphic sex is as depicted in the Stepping Stone and Maiden Rose series: Border is nowhere near as graphic as those. It's less explicit than U Don't Know Me, and just slightly more graphic than Little Butterfly, when Kojima and Nakahara finally get together.
Also ai_chan1 calls it small. I don't know if she means short, or literally small in dimensions. It is slightly smaller in height and width than some other yaoi although this doesn't seem to me to negatively impact the art. However in length terms it's a bit longer than most other yaoi GNs. Cheers!