The Shard of Tesla that caused the train incident is said to contain the notes for the Tesla Coil, and could trigger similar high-damage incidents in the vicinity. Botan and Kuruma act to recover the shard and prevent that, but are watched by another duo.
--I found it shining in the Aker River,
and brought it home.
وجدتها تلمع في نهر آكر  
.وأحضرتها إلى المنزل
Der hat in der Ager gefunkelt
und ich hab ihn …
Lo encontré en el Río Aker,
Je l’ai trouvé près de l’Akerselva.
मुझे यह अकर नदी में मिला था,
Achei ele brilhando no rio Aker,