Story

Twelve years prior to the start of the story, a legendary Hunter named Ging Freecss leaves his infant son, Gon Freecss, with his cousin Mito on Whale Island. Gon, raised believing his parents were dead, finds out from Ging's apprentice, Kite, that his father is still alive. As such, Gon 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. Another of the applicants in the Hunter Exam is Hisoka, a villainous examinee who takes it upon himself to test the worthiness of his peers attempting to become Hunters and takes an interest in Gon and his friends.
The Hunter Exam tests Gon's physical and mental strengths through a series of bizarre stages. During the final portion of the exam, after confronting his elder brother in a tournament, Killua is forced to return home to his family on Kukuroo Mountain. Determined to get him back, Gon, Kurapika, and Leorio all head to the Republic of Padokea to retrieve Killua, to what they succeed. After the retrieve, 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. By the end of the Phantom Troupe story arc, Kurapika has killed two members of the Troupe. These are accomplished via an unsteady alliance with Hisoka, who betrays the Phantom Troupe in exchange for a chance to fight Chrollo Lucilfer, though when he learns that Kurapika has sealed Chrollo's nen-abilities and loses interest.
Finally Gon and Killua's find the Greed Island, the seemingly-magical video game that sucks players within. It is later revealed that the game is actually set on an island in the real world, created and run by a group of powerful Nen users led by none other than Gon's own father, Ging. 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 'Ngig', who they believe to be Ging. However, it ends up bringing them to Kite instead.
Gon and Killua meet up with Kite, the Hunter who told Gon about Ging and Hunters in the very first chapter. They are all hired to investigate a strange insect leg that washed up on a beach. Genetic testing determines that the leg belongs to an abnormally large queen chimera ant, an insect that eats other insects and animals, and then gives birth to children that inherit the characteristics of all the different insects and animals it has eaten. The queen chimera ant itself happens to wash up on the shore of an island nation called the NGL (Neo Green Life) inhabited by a neo-luddite culture. She quickly develops a taste for humans after given the opportunity to eat them. The Chimera Ants proceed to wipe most of the population out and spawn hundreds of offspring before Gon, Killua, and Kite arrive.
The queen dies due to the King ripping himself out of her womb too early. With the Queen dead and their inhibitions gone, many of the warrior Ants proclaimed themselves kings and departed the hive; two of them end up joining the Hunters' side. The King and Royal Guard Ants pull a "coup d'etat" on the nearby Republic of East Gorteau and from there begin the process of "selecting" humans that have the capability to gain Nen powers. This causes many deaths as only a small amount of humans are able to gain Nen powers. As warrior Ants from the old hive rejoin the King, the Hunters mobilize quickly to stop the massacre.

credit:http://en.wikipedia.org/wiki/Main_Page