Ferrum's Secrets: where is grandpa?

Synopsis en anglais

Ferrum city was enveloped by a thick fog. Prominent citizens and scientists disappeared and among them well known inventor working on a number of inventions in the field of electricity. Shortly after his disappearance his granddaughter comes to his house. With her favourite kitten Iris, she must face the mystery and discover what happened to her grandpa. Will she manage to save him?