On a drizzley morning, Miss Monochrome wakes up in her four and a half tatami-mat sized apartment. When she tries to change her battery, a leak in her roof causes her battery box to explode. What should appear from the smoke of the explosion but a good-looking guy in the form of a battery! Miss Monochrome and Battery-kun are shocked by this destined encounter. Thus begins their days of friendship.
I'm here for you, so you're in reliable hands...
...أنا هُنا لأجلكِ، لِذا فإنكِ بين أيدٍ أمينة
Ich bin doch da. Überlass alles mir ...
Ya que estás conmigo, 
puedes estar tranquila.
Estás conmigo, así que 
puedes quedarte tranquila.
Tant que je serai là,
tu peux compter sur moi.
Ci sono io con te, sei in una botte di ferro...
Estou aqui, então você 
está em ótimas mãos...