Mega Man Battle Network 4^[a] is a video game developed by Capcom for the Game Boy Advance (GBA) handheld game console. It is the fourth game in the Mega Man Battle Network series. The European version featured a completely different logo, which was also used on Mega Man X7, Mega Man X8, Mega Man Zero 2, Mega Man Zero 3, Mega Man Zero 4, Mega Man X: Command Mission, Mega Man Network Transmission, Mega Man Battle Chip Challenge, Mega Man Battle Network 3, and Mega Man Battle Network 5. Like Battle Network 3 before it, Battle Network 4 has two different versions, Red Sun^[b] and Blue Moon,^[c] that differ in story and gameplay details. Battle Network 4 is compatible with the e-Reader, and can be linked up with Rockman EXE 4.5 Real Operation and the Battle Chip Gate for NetBattles. It is able to link with Mega Man Zero 3, and contains references to Konami‘s Boktai series.

Plot – MegaMan Battle Network IV Blue

At a space research center known as NAXA, scientists discover a massive asteroid speeding toward the Earth that would cause the extinction of all life. After a call is put out to the world’s greatest scientists, including father of the protagonists Yuichiro Hikari and a man known as Dr. Regal, they decide to direct the asteroid off-course with a laser. When that plan fails, Regal suggests searching for a world-class Net Operator and NetNavi.