Aaand literal cold armpits.
Gorgom sends their strongest mutant yet, the Mammoth Mutant to defeat Kamen Rider. Problem is his power is not enough to defeat Rider. This is when Professor Kuromatsu comes in and shows them the taurin extract that the mutant drank to become stronger. To give more power to the creature, they need to get more tuna, the main ingredient of the taurin extract, leading to reports of stolen tuna cases in Japan.
This is probably, one of the weirdest episodes of the series that I have seen. Aside from the seriously ridiculous plot of stealing tuna from warehouses instead of mass fishing tuna from the sea, we have a sushi chef who fought the Mammoth Mutant. The sushi chef's attempt to fight the mutant is quite admirable that I am okay seeing him wounded by it. That takes a lot of guts just to fight a monster with only a baseball bat and some cheap looking armor.
Because of this lead, Kotaro begins his investigation of where Gorgom possible store the tuna that they stole from various warehouses. While this is all happening, Katsumi, Kyoko and the sushi chef's son visited the sea, something that kid's father promised that they will do but they can't because of his injury. The reason behind it is simple; the kid wants to remember his dead mother. As for Katsumi and Kyoko, this scene showed us how much they miss Nobuhiko and their silent anger for Gorgom that the narrator revealed. What's interesting in this scene is that they sang their own version of "Long, Long Ago 20th Century", the ending theme of the series.
As for Kotaro, after discovering his lead, he did some more investigation and discovered that the Mammoth Mutant is still alive. The fight between the two is seriously fun to watch. If there is one thing that I discovered in this scene is that the Mammoth Mutant is kinda stupid. Stupid in the sense that he decided to return to the place where they are making the taurin extract, causing Rider to discover it. The way the facility is destroyed is fun to watch. To put it simply, it is destroyed because of Mammoth Mutant's stupidity.
The final fight between BLACK and the Mammoth Mutant is once again, really fun to watch. For once, the Mammoth Mutant is able to pin Kamen Rider with his icicles. But nope, our hero has one trick left in his sleeve and quite literally, it is found in his sleeve in the form of his Power Stripes! Much to my surprise, the red and yellow stripes in his body can actually release energy that is strong enough to melt the ice! Now that the ice is thawed, BLACK performs the finishing moves, defeating the Mammoth Mutant.
As for Kuromatsu, he is punished for his failure... even though it is basically the fault of the Mammoth Mutant. As for Kotaro and co., they got some free sushi courtesy of the sushi chef they met in this episode! To put it simply, this episode ended in a high note and I like it.