Reimu had a plan where she would dress up her child in Sanae's accessories so she could get close to Suwako and Kanako and kill them, putting Reimu as the clan's leader. Kanako and Suwako are looking for their missing child, and initially think that 'Sanae' is it, but a smart Tewi sees through the disguise, and the pair are punished.
As for Sanae, she's found by a Tenko-Yuuka pair and brought back to their clan, albeit without accessories. They try to pass her off as Yuuka's relative, but the clan (consisting of Wriggle, Cirno, Meiling, Shizuha and Minoriko) see through it easily. Luckily, they are easy yukkuri who are kind towards Sanae.
Suwako and Kanako find out about Sanae and come down to the place where she is. Kanako and Yuuka quarrel over who Sanae should stay with, while Tenko wants to make Sanae her 'queen'. In the end, she settles to divide her time between them, eventually becoming an ambassador of sorts. HAPPY END
Now for the right side. Reimu has been thrown out, but her Deibu babies pisses her off with their whining and insults, so she stabs them repeatedly to death, even when they beg for forgiveness. Due to eating their bodies, she acquires a taste of koyukkuris, and is pursued by a bunch whose koyukkuris she ate. She hides in a dirty ditch, then comes up with the idea that she can escape by becoming a pet.
I should have mentioned this from the start, but this Reimu is a shithead with a shithead level of over 9000. She thinks everyone else is beneath her apart from her children (which are still beneath her), and that everyone else should fall over themselves to serve her.
So she goes out on the street asking for people to take her in, thinking she's charming them with her beauty. But the fact is with all the sweets she has been eating, her teeth are decayed, and the ditch she hid in earlier makes her stink badly. Eventually she loses her temper and insults the humans.
The man who initially kicked Sanae and started the whole chain of events takes offense and brings her to a empty junkyard where he starts beating her around. But suddenly another guy shows up claiming to be from a yukkuri rights movement, scaring off the first one and taking Reimu home. She thinks she's got a great slave, and thinks she'll be able to take her revenge on Sanae when she sees the big house the man is in.
Already she starts insulting the man, but he tells her he has to clean her up before she can enter. That's when she finds out that he had lied about being a yukkuri rights follower, but an abyuser instead.
His method of cleaning involves a blowtorch, which he uses to burn her feet. Then he tells her she needs to get rid of her rotten teeth, which he does so with a drill. 'Raise your braids if it hurts', he says, but he didn't say he would stop. In the end, she loses all her teeth, even the healthy ones. Then he cuts off her braids, saying they're in the way, and finally burns her all over.
Abandoned out on the street, Reimu can only scream in her mind for help, thinking everyone should be lucky to help the great Reimu, and thinks about how she would revenge herself on Sanae. Then who should come across her but Sanae herself! But Sanae doesn't recognize Reimu even after staring at her for a while, and she can't hear Reimu's thoughts. Eventually she leaves, with Reimu cursing her silently.
Then she comes back, with Yuyuko and Myon. She tells Yuyuko that Reimu is a manjuu, and that for a manjuu, being eaten is their way of taking it easy. So Myon starts carving off Reimu's burnt skin, and Yuyuko feasts. Through the cutting, Reimu screams curses at the scum Sanae in her mind, but just before Yuyuko finally ends her life, she has a change of heart, and begs Sanae-sama to save her.
But of course, Sanae can't hear her, so Reimu dies.
Afterwards, Reimu is shown being tortured in hell. It is what she rightly deserves with her arrogant pride, and she will continue to suffer, even after a year, a decade, a century, a millenium.... forever.