Hot Ice, Cold Hearts starts off with three burglars stealing rare and exquisite diamond jewelry out of a museum. Later, they are hiding out on their boat in the waters near Avalon, a resort area in the Catalina Islands, where Quincy (Jack Klugman) and his girlfriend Lee (Lynette Mettey) are also enjoying the July 4th weekend on his boat. When one of the henchmen of the burglars is found trying to help himself to the goods, they inject him with the venom of a poisonous stonefish and throw him in the water to drown. He is quickly rescued and brought ashore where Quincy is called in to assist in reviving him. Quincy cannot fathom how the man was bitten by a poisonous fish native to Africa and also cries foul when the man later dies in the hospital of respiratory failure leading him to investigate further.
I didn't find this episode to be as strong as the ones that preceded it in terms of the plot or the guest stars. You will see many familiar faces of character actors that made the rounds appearing on many shows in the 70s, but I didn't find any of them to be that compelling here and felt their performances were more caricature. There are some especially ridiculous scenes where the sheriff is so frustrated by Quincy that he threatens him with violence and does some type of Kung Fu-like move. I also couldn't believe both of the murder attempts in the water were conducted in broad daylight with other boaters all over the place nearby and no one witnessed anything. Seriously??
One thing I did find interesting was that this episode takes place over the July 4th holiday and you see some bicentennial decorations in the background of various scenes since it was 1976. This episode aired in January 1977, so not sure if they actually filmed it right at the time of the bicentennial, but the timing seems to be about right.