Challengers (チャレンジャーズ, Charenjāzu) is a manga series by Hinako Takanaga. The first volume of this series was originally called Goukaku kigan (合格祈願, lit. "Prayers for a passing grade") before the series was retitled, Challengers. There is a spin-off series to Challengers titled, The Tyrant Falls in Love.
Tomoe Tatsumi, a high school student from Nagoya, goes on a trip to Tokyo to take a university entrance exam. He gets lost wandering around Tokyo when he runs into, Mitsugu Kurokawa, an office worker who had been out drinking with his friend Isogai. Isogai throws up on Tomoe and so Kurokawa takes him to clean his now ruined coat and tells him he'll help him find his hotel, but then they realize that the address to the hotel is in his coat pocket which is now in the wash, further complicating the situation.
Since Kurokawa has an extra room at his place, he offers to let Tomoe stay at his place for the night. Tomoe accepts and the next morning he goes off to take his entrance exam. When Tomoe is getting on the train back to Nagoya, Kurokawa kisses him. Tomoe appears shocked and appalled at this and Kurokawa thinks he'll never hear from him again, but is surprised to receive a post card from Tomoe telling him that he passed the entrance exam. When Tomoe returns to Tokyo to look for a place to live, he asks for Kurokwa's help and Kurokawa offers to let him sub-lessee the extra room in his apartment. Tomoe thinks it would be a good idea since it would save his family money and accepts the offer. Kurokawa eventually confesses his love to Tomoe and their relationship develops gradually, but not without interference from various friends and relatives.
Tomoe's short-tempered older brother, Souichi Tatsumi, is suspicious of the living arrangement and tries many times to get Tomoe to move back home. It is revealed that Souichi is homophobic because he was almost raped by one of his professors at his university but his lab assistant, Morinaga, saved him. As it so happens, Morinaga is gay and has had a crush on Souichi for 4 years starting from the moment they met. Souichi and Morinaga's story is continued in the spin-off series, The Tyrant Falls in Love.