The Hot Spring Investigation Arc is the ninth story arc of the Shokugeki no Soma series. After a 4 month time-skip, this arc focuses on Megumi and Sōma investigating a mystery at a local hot springs town.
Erina Nakiri assigns Soma and Megumi to investigate a crime regarding the chefs that have been missing to the hotel that was connected to Totsuki known as the Windvane Resort. In the first days of investigation, Soma couldn't find a single clue to the causes of the crimes. During their stay in the resort set up by Hisako, Megumi feels flustered in staying in a single room as they are going to sleep in one room during their stay. After their days of investigations, multiple crimes have risen and has caused other restaurants to close shops due to no service in their kitchens.
Soma suspected that since the chefs left, they would leave with just their property but when investigating the kitchens of the closed managements, he found that he didn't found a single utensil left in the premise. One time, when Soma was just hanging out in a nearby arcade, he meets a man known as Monarch. He has a king-like attitude but Soma didn't suspect him. Though he left, he was again committing crimes and he was caught in the Windvane Resort in the dark kitchens, where he saw a collapsed landlady on the floor but was just knocked unconscious.
Monarch sees Megumi and Soma and asks their relevance to the crime. Megumi, serious, jumped at the chance to challenge Monarch as her challenge was to impress Monarch's taste buds and palette. At first, the landlady and the staff thought that she had no cooking experience in the kitchen but Soma acknowledges her rank in the Elite Ten and that is an enough explanation to their problems. When Megumi gave her dish to him, he saw a very memorable dish in the American countryside, the Gumbo. She assumed that since he was wearing American-like attire, she would put on a dish that suits him. Furthermore, when Monarch hasn't yet tasted the dish, he suspected it to be a "dish for kids" as he thought it was curry. Soma then resolved the matter by letting him leave the premises.
The other Elite Ten members were also at other places to hunt for people who were making a fuss throughout the culinary world including people Erina thought had the potential to take down the administration installed by the Shokugeki. During one of the searches that the council assembled, they said that the head of their group was "Saiba". Erina and the Elite Ten Council was confused because the only person they know that had that surname is Erina's idol and Soma's father, Joichiro. Soma, confused, called his father to answer his doubts. As it happens, he says that he was his "son", but according to Gin Dojima, he said that he was his disciple. Soma and company looked for leads and as it turns out, he checked out a classroom with a new teacher called Suzuki.
When he entered, he saw him teach his class as he was giving out snacks towards his students. After this class, Soma and Megumi were discussing what he was doing in the classroom and according to his response, he said that it was just a dignified way to tell flavors. Suzuki felt proud that people with ranks like Soma was visiting his first ever class as a Totsuki professor. Minutes later, with intent, he challenged Soma to a Shokugeki. He was absurd, talking about making Erina Nakiri his wife as she is the only one who deserves his food. Soma agreed to the Shokugeki and started cooking. When it came to judging, Suzuki came out on top against Soma and revealed his real name, as he was masking his true identity as the leader of the group. His real name was Asahi Saiba, now confirming the identity of the Les Cuisiniers Noirs.
According to the trivia, these are the facts found about it.
- During one of the events that Joichiro joined known as Blue, he met Asahi there as his competition.
- Joichiro, being hailed as the best chef in his generation, was actually beaten by Asahi Saiba in a Shokugeki in a 5-0 unanimous victory.
- Asahi Saiba