Araragi is walking up the stairs to his class and catches a girl named senjougahara who is falling from the stairs and notices she's as light as a feather.
What's he looking at?
Are you lost?
DON'T TALK TO ME, I HATE YOU!!!!
Senjoigahara explains that she was cursed by a crab god who took her weight. Araragi asks Oshino for help and he summons the crab for her to ask for her eight back.
I'm gonna find Oshino or whatever.
Senjougahara begs the crab to let her have her weight back but realizes she lost her weight because she took the weight of her burdens off her shoulders and tried to forget about them all. She gets her weight back after she 'puts the burdens of her childhood on her shoulders' and decides to not run away from her problems.
I'm gonna force him to be my boy to be my boyfriend.
Araragi spends mothers day alone at a park because he got into a fight with his sisters. senjougahara joins him, and he sees a small lost child with a huge backpack that says the name "Mayoi" on it. He goes to ask her if she's lost and she gets mad and tells him that she'll never find her way home since she's just 'a lost snail' and that he should leave her alone
Araragi and Senjougahara go to search for Mayoi's mother's house after she explains that she was trying to visit her. They get lost several times and believe it could be due to a "snail ghost" so Senjougahara asks oshino for help.
Senjogahra tells Araragi that Mayoi is the snail ghost, and the only way to get her home is to take a route she's never taken. They find out Mayoi is a ghost that distracts people from reaching their destinations, which is why Araragi didn't want to go home to his sisters. They take Mayoi to where her mother's home used to be and she finally gets to rest in peace.
I should probably go home and apologize to my sisters.