Shoutarou is not satisfied with being separated from Sakurako, especially when it’s “for his own good,” but as of the start of the episode, he has yet to gather the courage to confront her about his displeasure. That is, until he reminisces about the time he first saw her (she put a spell on him with her ethereal beauty) first called the cops on her (when he saw her boiling bones), and accompanied her on their first case as a mystery-solving duo, during which Sakurako did all the heavy lifting.
The case involved an elderly relation of his neighbors, who had the urge to visit a certain shrine. Sakurako canvases the shrines and determines the old lady murdered the man she finds buried beneath the tree, and does her Sakurako thing that transforms her into the young girl she was when she did it, in order to save her mother from her father’s beatings. It packs the usual emotional punch of such encounters throughout the show.
The part of the flashbacks pertinent to Shou’s present predicament is Sakurako’s assertion that “time stopped” for Yachi-san when she killed her father. Her regret kept her standing still, no better than a still-living corpse, just waiting to die. But time never stops for anyone, and stopping in fear of the future gains nothing, according to Sakurako’s past self. Shou now has all the inspiration he needs to face the present Sakurako-san, and all the ammo he needs to get her back in his life, and him back in her’s.
So Shoutarou storms back on to her property, declares he wants back in her life, and won’t take no for an answer. Like the first time they met and he followed her around, he’s come to “escape his everyday life”…only he wants his everyday life to be one with Sakurako in it. Saku warns him of the “abyss” Hanabusa, and by extension she, represents, and how she dreads seeing Shoutarou’s bones. But he rattles off all of the people she saved from Hanabusa’s machinations—Ii-chan, the baby, Fujioka-san—as well as two of the three girls who worshipped Hanabusa, along with Yuriko’s peace of mind.
With that track record, Shou feels safer with Sakurako than without, and asks her to continue protecting him. Defeated, Sakurako agrees, and we know she’s a bit relieved herself that this boy shook her out of her attempt to carry on alone. So much so, she calls him by his name again, without reservation; a sign she herself may be willing to keep moving forward beyond whatever dark mysteries are in her past, or whatever skeletons are in her closet.
Shou is well aware their path won’t be an easy one; Hanabusa is definitely watching them and will try to tap into their grief and regrets and despair just as he has his many victims. But in a battle of wits between him and Sakurako, there is no choice for Shoutarou: Sakurako will win. Especially with an excellent assistant such as himself by her side.