 In a rare episode to delve deeply into native-Hawaiian culture (the last episode for Alvin Sapinsley, the show s most daring writer and perhaps its best), McGarrett and company are called in when an archaeological dig on The Big Island reveals secret tunnels headed underneath the ocean, which could lead to the grave of King Kamehameha I. Or at least somebody believes so, donning a royal robe and mask to frighten off -- and later kill -- two members of the archaeological dig. This is a rare episode in which the killer is not revealed until the end; in fact, McGarrett has to mark the case as unsolved because the killer cannot be brought to justice. (See also "Invitation to a Murder," episode #10.20, from later this season.)