Back to the Inn where the Itto-Ryu boys had their big party.

Magatsu approaches the place, and notices that there's crows all over the place (crows pick at garbage and refuse).  When he approaches the inn, he notices the horrible smell... Masaka!

Yep.  Everyone's dead.  Two days dead.  That can't smell too good.  I'm glad this manga isn't "scratch and sniff"...

It's Abayama!  You know, the smart guy who makes all the plans for Itto-ryu.  And he's alive...

He's also upset as hell, grunting in shame:
(Magatsu: Who did this?)
Abayama: It was just... TWO PEOPLE!

Apparently in the food that was given out they used a certain poison mushroom (tsukiyotake) that, when cut, looks like shiitake.  It doesn't kill you, but it makes you sick to your stomach.  The Mugairyu guys jumped them when they all started to cramp up.

Magatsu starts remembering... Back at that time he was in the carried sedan and was almost assassinated, when he stabbed the assailant, he said his master was "Akagi"

When he thought about it, the "A" wasn't part of his name, it was a "dying breath".  He meant to continue, but died before he could finish his words.  He didn't mean Akagi, but

"Kagimura!"

Kagimura, of course, being the guy who hired Itto-ryu to work for the government. Magatsu realizes the depth of the betrayal. Oooh!

One thing that caught me off guard- This is the last of the "Last Blood" story arc.  For a while I was thinking that this was going to be the last story arc of the series.  I'm glad that I was mistaken!