After the abduction of his brother Kotaro by the Machine Empire, Teppei Takamiya joins forces with X, one of several highly-advanced, artificially intelligent machines known as B'ts (pronounced 'beat'), to rescue him.

Volume Subtitles:
1: X Revival! (エックス復活!, Ekkusu Fukkatsu!)
2: Far Way to the Area (エリアへの遠い道, Eria e no Tōi Michi)
3: Heart Color (心の色, Kokoro no Iro)
4: Five Color Phosphorescence (五色の燐光, Goshiki no Rinkō)
5: The Seven Greatest Demons (最凶の七魔将, Sai Kyō no Nana Ma Shō)
6: Fragment of the Sun (太陽のかけら, Taiyōnokakera)
7: Song of an Angel (天使の詩, Tenshi no Uta - ALT ENG. Angel's Poem)
8: Forest of Oblivion (忘却の森, Bōkyaku no Mori)
9: Nightmare Battlefield (悪夢の戦場, Akumu no Senjō)
10: Blood Battle! Kamui Island (血戦！神居島, Kessen! Kamui-Jima)
11: Area Collapse (エリア崩壊, Eria Hōkai)
12: Shellfish (貝えぬもの, Kai Enu Mono)
13: Deathmatch of Intelligence (智力の死闘, Chiryoku no Shitō)
14: Faithfulness (信しる心, Shin Shiru Kokoro)
15: Hurry Light! (光よ急げ!, Hikari yo Isoge!)
16: Eternal Path (永遠の軌跡, Eien no kiseki)

Note: Volume count based on the bunkoban.

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