In 1999, Hunter × Hunter was adapted into a 62-episode anime television series produced by Nippon Animation and directed by Kazuhiro Furuhashi. The show premiered on Japan's Fuji TV and ran until 2001. Three separate original video animations totaling 30 episodes were subsequently produced by Nippon Animation and released in Japan from 2002 to 2004. A second anime television series by Madhouse aired on Nippon Television from October 2011 to September 2014, with two animated theatrical films released in 2013. There are also numerous audio albums, video games, musicals, and other media based on Hunter × Hunter. The manga has been translated into English and released in North America by Viz Media since April 2005. Both television series was also licensed by Viz, with the first series having aired on the Funimation Channel in 2009 and the second series airing on Adult Swim's Toonami on April 16, 2016.
Twelve years prior to the start of the story, the famous Hunter Ging Freecss left his infant son, Gon Freecss, with his aunt Mito on Whale Island. Gon, raised believing his parents were dead, finds out from Ging's apprentice, Kite, that his father is still alive. Gon then leaves his home to follow in his father's footsteps as a Hunter by taking the Hunter Exam. Prior to the Hunter Exam, Gon meets and befriends three of the other applicants, Kurapika, Killua Zoldyck, and Leorio. After the exam, Kurapika departs to find work and Leorio leaves to attend medical school. Gon and Killua decide to gain combat experience by training at the Heavens Arena, a 251-story building where over 4,000 fighters compete daily in fighting tournaments. There, they meet the kung-fu master, Wing, who teaches them about Nen--a chi-like life energy that can be used to manifest superhuman powers.
The third story arc reunites the main characters for the world's largest auction in a sprawling metropolis called Yorknew City. Gon, Killua, and Leorio try different methods to make enough money to buy Greed Island, a video game that could help Gon find his father. This story arc introduces the Phantom Troupe, a group of thieves who, among many other crimes, slaughtered all the other members of Kurapika's clan. Kurapika crosses paths with them while working as a bodyguard. Finally, Gon and Killua find the Greed Island, the seemingly-magical video game that sucks players within. The goal of the game is to collect a number of set cards, although almost everything in the game, from food to money, can be turned into cards. Inside Greed Island Gon and Killua are joined by Biscuit Krueger, a master and experienced teacher of Nen who trains them. As part of their reward, they are allowed to take three cards to be used in the real world. Using the card 'Accompany', Gon and Killua travel to a player under the username 'Nigg', who they believe to be Ging. However, it ends up bringing them to Kite instead.
Alongside Kite, Gon and Killua briefly work as biological researchers in the country of Kakin. As they investigate a giant insect limb found on the country's shores, the group discover it came from a man-sized chimera ant queen — an insect that devours other insects and animals and then gives birth to progeny that inherit the characteristics of the different species it has eaten. The queen chimera ant washes up onto island nation called the Neo-Green Life (N.G.L.) Autonomous Region, inhabited by a neo-luddite culture. She quickly develops a taste for humans and builds a colony in order to conceive both an army of offspring and a chimera ant king. The chimera ants proceed to wipe most of the population out before Gon, Killua, and Kite arrive. The queen dies during labor, and the chimera ant king and his Royal Guards flee the N.G.L., secretly overthrowing the government of the nearby Republic of East Gorteau soon thereafter. Under the guise of the former king of the Republic, the chimera ant king initiates the process of forcibly awakening Nen in the civilians of East Gorteau in order to form his own personal army to conquer the world — resulting in the deaths of millions unable to awaken Nen. As ants formerly under the queen's rule rejoin the king, the Hunter Association mobilizes quickly to stop the oncoming genocide by sending in an extermination team of Hunters to East Gorteau. Distraught over the murder of Kite at the hands of the Royal Guards, Gon and Killua join the extermination team in order to take revenge for their friend.