is a Japanese harem manga series by Takeshi Fujishiro. It was first serialized in Square Enix's Monthly Shōnen Gangan magazine in January 2002, and a few years later expanded into a multimedia franchise including drama CDs, light novels, and a 26-episode anime adaptation by Studio Feel that aired in Japan between April 4 and September 26, 2007.

From the same author, there is a sister series titled Cahe Detective Club which features the cousins of certain characters from this series.

Plot After an argument with his father, 14-year-old Ikuto Tōhōin runs away from home and out to sea, only for a massive storm to send him adrift and eventually strand him on an uncharted tropical island named . Half-drowned, he is found by a kindhearted but naive girl named Suzu, who (clumsily) resuscitates him and takes him into her care.

Soon after, Ikuto learns that Airantou was settled 130 years ago by a group of Japanese that had been shipwrecked during a voyage to Europe. Though their Meiji-era village survived and prospered to the modern day, its entire male population was claimed by a rogue wave during a fishing tournament some twelve years before. As a result, nearly every girl of Suzu's generation is desperate for a husband and immediately latches onto Ikuto as a prime candidate; to his dismay, their attentions quickly erupt into violent competition, forcing Suzu to protect him.

At first eager to escape the island (and stymied only by the quasi-magical whirlpools surrounding the entire coast), Ikuto eventually settles into his new life with Suzu, befriending her as well as many of the other girls pursuing his hand. Together, they engage in countless mishaps and adventures, heartily encouraged by not only the village matriarch – Suzu's grandmother – but the increasingly large cast of anthropomorphic animals and Yōkai that also call Airantou home.

Characters

(drama CD), Hiro Shimono (anime) Ikuto, age 14, the main character, is stranded on Airan Island. He has inherited his grandfather's determination; the words "It's impossible!" send him into a state of berserk tenacity, usually accomplishing his goal or getting struck unconscious trying. Ikuto completely refuses to accept anything supernatural. It is revealed that a cryptic jutsu was cast on him by a specialist (Nagamasa) to make him reject anything occult, to not make him think Misaki is not human. Three years ago, his mother went missing during her trip to Okinawa. One day, he overheard his father and his grandfather's secretary (Hiragi Iwatsuki) talking about marriage. He misunderstood and decided to skip school to search for his mother to cancel the marriage, but his father found out they started to argue. He ran away on a cruise liner, arriving on the island due to a storm. Kind and helpful, Ikuto's physical ability pales in comparison to that of the women on the island at first; in the beginning he cannot understand any of the animals on the Island whereas the women can (he can understand later). Conservative, Ikuto finds it difficult to accept Airan's freeload customs. Due to the Island's girls inexperience with boys they'll often try to seduce him, which results in most of the time in failure or Ikuto having an exaggerated nosebleed and passing out. Ikuto refuses to do anything towards them, as he thinks that they only care for him because he is the only male on island. He starts training with Karaage, after realizing his swordsmanship had decayed after he came to Airan. Ikuto is actually very smart however, acting as the island's math and science teacher, and loved to read mystery novel, proving he is very rational. Suzu seems to be the only one who has genuine feelings for Ikuto from the start though she does not realize it until later, and he develops feelings for her (and Rin) due to her kindness, but seems to deny these feelings, thinking that Suzu only sees him as family. Ikuto develops a strong rivalry with Beniyasha (Chikage's mother) who creates mischief on the island to publish his novels, especially when he flirted with Suzu that made Ikuto really jealous. In the second son-in-law contest, Ikuto won due to his training able to deceive or at least land a hit on each of the lords. Upon Ikuto and Misaki's reunion, their grandfather has been locating Ikuto aided by former males of Airan: Nagamasa, Machi's and Ayane's father; Tadanori, Rin's father; Hideaki, Yukino's father; Kiyomasa, Chikage's father; Takatora, Suzu's father; Hanzou, Shinobu's father; and Masamune, Misaki's biological father.

(drama CD/anime) Suzu, age 13, is the main female character of the story. She is an honest girl and can be very spontaneous when excited. She is the first person that Ikuto meets on the island and possibly the closest one to him. As the series progresses, Suzu develops feelings for Ikuto, but at first, she has trouble realizing it due to her inexperience with boys. Later on, she gets very jealous whenever another girl gets close to him (Manifested as a dangerous aura shaped like a murderous cat) and even attempts to have him kiss her by pretending she drowned and attempts to have a date with him. She does not mind being naked around Ikuto and does not understand why Ikuto always gets nosebleeds and passes out whenever this happens, especially when she attempts to bathe with him that she enjoys. She is still very happy to have him in her life, since she had been living alone with her pet piglet Tonkatsu (lit. "breaded pork cutlet") due to Suzuran's disappearance. Suzu loves sweets to the point where she can be easily bribed with them, especially with the special "Mame Daifuku" treats made by Ayane's and Machi's mother. Suzu is one of the best players of shogi and other strategy games on the island, to the point that she could easily beat Ikuto. She is also good at jujutsu, and was trained by the Southern Leader because she once threw Ayane on top of a tree; although her mother was even stronger than the current Western Leader, she did not teach Suzu Jujutsu, probably due to that she wants Suzu to be more feminine. However, Suzu lacks basic education compared to most of the girls on Airan as she cannot comprehend simple mathematics and tries to skip school as much as she can. Ironically, she has demonstrated an aptitude for deduction, which is associated with intelligence and logic. She is also torn between her feelings for Ikuto and a wish that Ikuto could get off the island, although she wishes he would stay, she knows that he has his family on the outside world, and it would be wrong to keep him here.

(drama CD), Saeko Chiba (anime) Ayane is Suzu's rival, always being defeated by her and wanting to win at least once. The fact that she constantly loses makes Suzu somewhat doubtful of her ability as an individual. In spite of her appearance, she is actually 16-years-old, and being underdeveloped she is also jealous of Suzu's sudden growth; nevertheless, she is close friends with Suzu, usually being the first to accompany her house when Suzu's mother had disappeared. She is arrogant, often saying she is the handiest and prettiest girl on the island. She is deathly afraid of Machi, her older sister, and uses anesthetic darts as her main weapon. She hopes to take Ikuto captive and trump Suzu. She is a miko at the local shrine along with Machi and their mother Chizuru (whom Ikuto mistook for her sister at first). She also frequently uses a giant ostrich named Monjiro as transportation. Out of the series's main characters, Ayane is the most frequent victim of violent slapstick; her body has great tolerance to pain due to her extreme bad luck which caused her a great number of accidents daily. She loves super spicy food, as they are the only food Machi would not take from her. After accidentally kissing Ikuto (chapter 69), she finds that she cannot approach him without getting flustered as she developed real feelings for him. She is very intelligent being the best prankster on the island, except for Machi who almost seems to play pranks on Ayane herself. Throughout the manga, despite her scheming personality, she is actually the most pure-hearted, usually being the most considerate in situations. For example: being the only one who did not try to spy on or sabotage Ikuto and Mei-Mei's date, actually giving them a scroll with suggestions on the best date-spots on the island, and being able to remember Michiru's name while others get it wrong.

(drama CD), Mikako Takahashi (anime) Machi is Ayane's elder sister and, despite being smaller than Ayane, she is actually 18-years-old. Despite her innocent looks, Machi is something of a sadist; she often tortures Ayane with her voodoo doll, finding beauty in her pained, frightened expressions. She also tends to take the most dangerous methods to getting things done. In her childhood, she often doted on her baby sister, but at some point, transitioned into terrorizing her. She alludes to the fact that the more she tortures people the more she likes them, suggestion her sadistic acts may be her own sign of affection. She sees herself as well past the appropriate marrying age and pursues a romance with Ikuto to avoid becoming an old maid. Her age is her biggest insecurity, and she becomes depressed whenever someone calls her old. She has a talent for magic, such as summoning shikigami, though she usually ditches all other cleaning and cooking duties at the shrine. Like her sister Ayane, she is quite proficient with using the blowgun. Machi has a habit of making surprise entrances (such as trapdoors and open ceilings).

(drama CD), Ryōko Shiraishi (anime) Rin is an apprentice carpenter who is popular on Airan due to her somewhat tomboyish outfit and attitude, she was the subject of a lot of attention and romantic interest from other women before Ikuto's arrival. She found this situation so uncomfortable that she developed a tendency to bathe alone. Despite her masculine mannerisms, Rin is shown to be appallingly bad at her hard labor job of carpentry and quite skilled with domestic chores such as cooking and sewing. Initially, Rin propositions Ikuto to be her husband to prove her heterosexuality (and so end the advances made on her by the other girls); however, she and Ikuto soon develop real feelings for each other. She calls Ikuto "danna" ("hubby" or husband), much to Ikuto's chagrin. She is the strongest person on the island, which hurts her feminine pride, but she secretly was proud of her appearance. She loves to dress up, but she at first embarrassed as she thought she was not feminine enough to look good in them, till Ikuto said she look pretty.

(drama CD), Shizuka Itō (anime) Chikage is obsessed with scientific research, and wants Ikuto for the sole purpose of examining a real male and learning about the world beyond the island from him. She collects things that drift in from the modern world and plans on adding Ikuto to her collection, seeing him as a potentially invaluable source of information. Chikage lives in the only Western-style house on Airan with her elephant maid, Panako. She has a habit of reading mature magazines and gets misguided ideas from them to use against Ikuto. Although Ikuto believes her to be a calm, well-behaved girl, Yukino has noted that Chikage tends to perform strange experiments and questionable research. In the manga, and episode 17, she proves the truth of this statement when she briefly gains access to magic and causes havoc around the island until it is taken away by an angry Panako. Chikage soon becomes fascinated with the novels brought by Ikuto (unaware that the author is her father). In the beginning of volume 12, she explains that she, Yukino, Kunai, Shinobu and Mikoto are cousins which explains her occasional appearance in Shinobi suit.

(drama CD), Shizuka Hasegawa (anime)