In the Land of Leadale, Vol. 7 (light novel)

Cayna, Opus, and their three servants are enjoying a bit of rest and relaxation in the remote village when Cayna decides to upgrade one her items: the Pair of Eyes, which transmits footage remotely between two eyeballs. She intends to use it so that the villagers can see and hear things happening in far-off lands. In order to locate this exclusive function, Cayna must return to the Guardian Towers that her old friends left to her, and this time she s bringing Opus and Siren in tow!