Act I, or Episode 1, is the first episode of In Search of Dr. Riptide. It is the only episode in the Shareware version. It does not have an official title. It consists of seven levels plus a secret level. The episode does not follow a consistent theme; it varies from natural caverns to a lab and ruins. Oscar is the episode's boss. In the Shareware version, completing this episode shows scrolling story text, states if the secret level was found, and shows images and ordering information for the full registered version.