Taking place one month after the events of the first Mega Man Battle Network, the plot follows the protagonist Lan Hikari and his "NetNavi" avatar MegaMan.EXE in their fight against the "WWW (World Three)" organization as it attempts to unleash and spread the infectious "Zero Virus" into cyberspace. The player controls MegaMan through a set of levels that require actions such as jumping, sliding, and shooting, as well as the use of special "Battle Chips" that grant the player various combat and platforming abilities. Network Transmission combines action and platforming gameplay elements from older Mega Man games with the strategy and role-playing elements as defined by the Battle Network series.
Source: Wikipedia, Mega Man Network Transmission , available under the CC-BY-SA License.