Episode Title:
The Basking Shark.
Episode Description:
A probe sent to study the planet Neptune's atmosphere returns to earth after 12 years but on reentry the parachute fails and it crash-lands in the ocean near Sealab. Mr. Mills from the Aerospace Bureau enlists the help of Sealab to help recover the probe within 48 hours. An anomalous malfunction with the sonar system and perceived sudden disappearance of the probe lead Aerospace to suspect Sealab sonagrapher Henry Lucas of espionage. The probe turns up in an unusual place and is retrieved in an even more unusual way.
