The city of METRU NUI is divided into six parts. Each part has a guardian — a TOA — who watches over the MATORAN who live there. However, something strange is happening: MATORAN are vanishing and a mysterious plant is destroying the city piece by piece. The TOA have to stop the disappearances and find a way to save their city. Do they have the skills to solve this mystery? Or will they finally meet their match?

That’s the description on the back of the cover, but it’s a bit misleading. First of all, the city is divided into six parts, but the TOA METRU aren’t even around at the beginning of the story. Well, that’s also misleading. Following the trend set by BIONICLE Chronicles #4: Tales of the MASKS , this story is told by the TURAGA in flashback, as the MATORAN are nearing their preparations to leave the island of MATA NUI and return to their long-forgotten homeland of METRU NUI. And what a flashback it is.

On the very first page it is revealed that it’s been “thousands of years” since the MATORAN have set foot on METRU NUI, and we already know that the current TURAGA were the TOA METRU of old. The story largely focuses on the TOA METRU and METRU MATORAN that have recently been released. One other familiar name, KAPURA, shows up at the beginning of VAKAMA’s tale, but I can’t recall any of the other MATORAN characters ever being identified by name. TOA LHIKAN and TURAGA DUME are mentioned, but never feature in the story. The MORBUZAKH plant and NHIDIKI are the only major villains of note (aside from the one MATORAN traitor), but a few familiar villains from the first story-arc also make brief cameos.

Of the five books released so far, this is the only one that seems to end in a cliff-hanger, with the heroes not mistakenly celebrating their final victory.