Hawaii Five-O

Danno and a college professor are kidnapped by a revolutionary group of young radicals led by a hardened criminal.

A geophysics expert, Bernard Brown, is heavily in debt, so he comes up with a plan to cause an explosion in the Hawaii Volcanoes National Park, which will cause lava to pour all down the hillside and into the city of Hilo, unless the Governor comes up with half a million dollars as a ransom.

Eddie Josephs is a paranoid schizophrenic who is carrying out murders based on old Five-O cases. McGarrett must follow his clues and catch him before more people die.

A sophisticated thief is selling his goods to legitimate businessmen, and Five-O must find a way of trapping him.

Senator Harlan Henderson suffers from multiple personalities, and one side of him wants to kill himself. However, he ends up blowing up his secretary, and McGarrett uses handwriting and a diagnosis from a psychiatrist to try to crack the case.

A criminal, Hobart, is robbing liquor stores using a policeman's former gun, but the officer wants it back as he used it to kill a bankrobber five years before and the body has been uncovered.