The following contains spoilers for The Devil is a Part-Timer! Season 2, Episode 11, "The Devil Preaches Human Interaction," now streaming on Crunchyroll.
Deciding to locate more shards of Yesod on her own, Emi uses the magic of the crystals currently in her possession to find the remaining ones. While performing this task, Maou, Suzuno and Ashiya meet with Rika at a shopping center to consult the latter about buying a mobile phone and a TV. Rika thinks this is strange at first, but soon comes to understand why Ashiya wants her advice when she points out she needs to upgrade her current TV to a 4K version, and he doesn't know what she's talking about. She then invites them to lunch to discuss the basics.
During lunch, while Suzuno marvels at the cheap price of her delicious udon meal, Ashiya and Maou discuss with Rika their budget constraints. In the midst of this conversation, Suzuno accidentally lets slip that she's not Japanese when she points out she doesn't know much about the country's consumer culture and Rika wonders if she was raised in a foreign country. She "confirms" that she was and explains her ignorance of electronics as being raised in a developing country where that wasn't a luxury, and avoids giving away the fact she's from another world.
When Suzuno decides to get a second serving of her udon noodles, the group encounters a foreigner talking to the cashier in English, though she only speaks Japanese. Maou decides to help the cashier by translating his request while telling the foreigner not to hassle her as it could get him -- and other foreigners -- banned from the place. This action gets Rika to question how Maou is only a part-timer if he can speak fluent English. Ironically, the moment the foreigner leaves, he shows he actually speaks fluent Japanese and questions why he bothered to learn English if it isn't the "language of the world." He also scolds the person on the other line for not telling him their target would be in Japan, hinting that he may actually be celestial in origin.
In another part of Tokyo, Emi continues to follow the path of her Yesod shard, only to find herself at a hospital. Coincidentally, Emi runs into Chiho's mother and quickly learns her daughter's been hospitalized. When Maou and his group arrive at the shopping center to buy their TVs, Suzuno immediately starts looking for the one she wants. Since Suzuno mentioned earlier she has ¥70,000 to spare, Rika thinks Ashiya should shop with her so that they can potentially get a discount on one of the TVs if they buy two together. Ashiya is grateful for this advice as it can leave him with enough money to buy a mobile phone. His reaction leaves Rika feeling flustered, which causes Maou to work out she has a crush on him.
Soon after they purchase their TVs, Maou invites Suzuno for tea to discuss the fact Rika has feelings for Ashiya. Suzuno thinks it's bad idea for them to get together as it would only lead to a tragic future. Maou, however, suggests that they tell her the truth about themselves being demons in a way she'll believe, and let her decide for herself if she still wants to pursue a relationship with him. Suzuno still thinks it's a bad idea to let more humans in on their secret, and that her rigidity on this matter is not without foresight. The communication style displayed by Maou and Suzuno in conversation has Rika questioning if they really are friends. Ashiya vaguely states they shouldn't be friends, but discussing their history is too complex to share at this time.
Deciding not to dwell on Ashiya's secret, Rika instead shows him some pamphlets and invites him to start shopping for the mobile phone. Before Ashiya has the chance to follow up on Rika's offer, a series of television screens are inexplicably destroyed inside the store. Maou advises that Ashiya escort Rika back to her home while he and Suzuno look into the TV incident. As Rika and Ashiya leave, Suzuno speculates that the incident could be the doing of Barbariccia's faction. Maou agrees and believes they should contact Emi and Urushihara. Coincidentally, Emi calls Suzuno at that moment to inform her Chiho's been put in a coma by some potent magic and that she's in the hospital.
Maou and Suzuno immediately meet with Emi and Chiho's mother at the hospital to discuss what happened. Chiho's mother reveals she found her in a coma when she arrived home at around dinner time and wasn't able to wake her up. When she called for an ambulance, neither the EMTs nor doctors were able to revive her nor pinpoint a cause for her coma. At best, they all know her life's not in danger. After Chiho's mother leaves Maou and his friends in charge of keeping an eye on her daughter while she runs some errands, Suzuno reveals her theory on what really happened to the girl. She believes someone had struck Chiho with a celestial force-based pulse, which effectively converted her life force into magical energy and induced her coma.
The moment Suzuno concludes her theory, another TV bursts in the hospital lobby, and Suzuno confirms that this is the result of a celestial sonar. Maou and Emi decide to check up on Chiho while Suzuno and Ashiya investigate the remainder of the hospital for an individual capable of using such power. Before they start their investigation, however, Urushihara meets up with Ashiya and Suzuno and informs them of Gabriel's visit and that the celestial sonar may be the work of Raguel the Watcher. When they meet with Maou and Emi in Chiho's room, Urushihara reveals everything he learned from Gabriel at their apartment, making Maou aware of the fact he's looking for the treasures of the Legendary Demon King Satan.
Despite not being a high-ranking angel, Suzuno knows Raguel is still given the authority to monitor the activities of other angels, and cast judgments and punishments as he sees fit. What doesn't click for Suzuno, however, is why only Chiho was affected by celestial sonar and not other TV viewers in Japan. Maou reminds her that Chiho's home was once the epicenter of a sonar pulse expulsion, though this leads Emi to realize something else. If the Watcher is in Japan, then this confirms her own mother, the mysterious Lailah, is also in the country. After Chiho's mother returns to the hospital to be with her daughter, Maou and his friends leave and Emi uses the opportunity to ask Urushihara what happens to angels who get judged by Raguel.
According to Urushihara, one possible punishment for an angel is to be cast out of Heaven like he was. Under normal circumstances, this would entail Sariel and Raguel stripping the angel of their immortality and banishing them to Ente Isla. In other cases, the angel is killed. Knowing this information, Emi decides she needs to protect her mother from the Watcher since she just learned of her existence and wants answers from her. Before she can search for her mother, however, Emi lends her cooperation to help locate the Watcher to hold him accountable for the harm he's caused Chiho. Since he's using TV signals to make his presence known, this narrows his potential location to two places.
Back inside Chiho's room, her nurse is revealed to be Lailah, who is also the reason Emi's Yesod shard initially brought her to the hospital. With Lailah fully aware of Chiho's situation, she gives the girl her ring containing another Yesod shard. While placing the ring on her finger, Lailah hints that Chiho will become the future mother of a new Daath, which explains her own interest in protecting her.
Based on the popular light novel series by Satoshi Wagahara, new episodes of The Devil is a Part-Timer! stream every Thursday on Crunchyroll.