Technically, the American Samurai arc starts with #11–but #10 has some groundwork after a stupid Wolverine cameo where he fights with Elektra’s boyfriend, a former heavyweight boxer.
It’s ironic–her boyfriend is jealous of Logan, but in this very arc Elektra makes out with Daredevil.
For the main story: Elektra and Daredevil track an American soldier possessed by the spirit of a samurai who is killing a street gang that dresses like clowns.
He also can teleport.
The story is mostly DD and Elektra tracking him as he murders a lot of criminals. At one point, he teleports into Sing Sing prison and just starts slaughtering guys.
In the end, the heroes stop him and he commits ritual suicide.