キズナの物語 (Kizuna no Monogatari, translated as "Chain Story" in English-region releases) is the opening theme of Chain Chronicle (チェインクロニクル), a mobile tower-defense role-playing game published by SEGA. The song was performed by Trefle, a six-member voice actress unit active from April 2013 to November 2016, whose lineup included Yui Ishikawa, Yui Kano, Chihiro Ikki, Yukari Goto, Minami Takahashi, and Marina Tanoue. Composition, arrangement, and co-lyrics were handled by Yosuke Sakanoue (サカノウエヨースケ), with additional lyrics by Izumi Takakage (イズミタカカゲ). The track originally appeared on Trefle's 2013 album アニソン神曲 + チェンクロ before being added to maimai.

In maimai, キズナの物語 debuted on April 7, 2014 as part of the GreeN PLUS update. Over its lifespan the song has shifted between in-game genres, originally classified as GAME, then SEGA, then ORIGINAL during the early でらっくす era, and finally settling into GAME & VARIETY, and its difficulty levels have been rebalanced several times across version updates. The Master chart (level 13, constant 13.2), designed by はっぴー, is notably slide-heavy with 140 Slide notes out of 356 total, a signature trait among the song's charts. The Expert chart was designed by Jack. Despite its relatively modest BPM of 128, the Master chart's dense slide patterns give it a distinct rhythmic character that sets it apart from other mid-level charts in the same version era.