You should know that it's three 10minute episodes. They could have just made one 30minute episode, but whatever.
So Masaru's mom Saori asks him to run an errand at Aunt Miyuki's house.
Masaru sees his aunt masturbating to porn an she's saying Masaru's name.
She catches him and invites him in and, oh yeah, incest time.
But wait Aunt Miyuki reminds Masaru that Saori isn't his real mom (whenever an incest hentai takes the time to remind the viewers that there is no blood relation I always laugh). So the f*ckening begins, and it's a good sex scene, good positions...
But wait a minute, folks, looks like there's a new challenger, it's Saori, Masaru's mom, oops I mean "step-mom". She wants to join in the action. And we have a good ménage-à-trois.
Masaru receives a phone call and has to leave. Will this mysterious phone call be addressed in the sequel INKO? We'll see.
After Masaru leaves the two sisters "entertain" each-other, but wait they're blood related, so we get our incest after all. And yuri too.
An enjoyable watch.