It’s hard to top the “Hawaii Five-O24th episode from last week for powerful performances and emotional pull, but viewers hungry for suspense and a taste of Italian cuisine had something in store with the May 18 Season 8 finale, “Waiho wale kahiko (Ancients Exposed).” Some paddlers, out for some rigorous exercise at sea, get the scare of their lives when a Russian nuclear submarine rises above the waves.

“Hawaii Five-O” arrives en mass to the beachfront, and calls are made from the governor's office all the way to the West Wing and onto president Putin.

As always, Lt. Commander Steve McGarrett (Alex O'Loughlin) wants to get a first-hand look at the situation, but seeing what’s happened on board only begins this story of embedded spies all over the islands.

Cooking lesson interrupted

Danny (Scott Caan) and Steve are back to the characteristic back-and-forth bickering that brings them into couples therapy when Danny bemoans the financial state of their restaurant, and still not ready to open, with nickels and dimes dwindling.

Steve is engrossed in an online tutoring session from Rachael Ray, and he assures his partner that everything is going to be “fine,” despite a “drastic” step. Danny insists that Steve needs to be under “concussion protocol at all times.”

Just in time, Nehele (Kekoa Kekumano) turns up with Kamekona (Taylor Wily) and Flippa (Shawn Mokuahi Garnett), each toting a large suitcase. After a cursory review of a contract drafted by McGarrett that is “not going to do it” according to Kamekona, the shrimp vendor offers a considerably heftier agreement, with “protection” for his large investment of $250,000, packed into the suitcases. The longtime buddies are mistrustful of banks, and seeing the cash makes Danny considerably more open to the idea.

The “silent partners” are prepared for both bust and boom of the restaurant when news of the submarine beckons.

More than mutiny

When the full “Hawaii Five-O” contingent arrives, people on the beach are as terrified as the paddlers at the sight of the Russian sub, which Junior (Beulah Koale) immediately identifies as the most ominous and powerful of the Russian fleet. Steve gets the identification of the vessel as the Gorskov, and initially uses his skills at Semaphore to make contact, before opting to borrow a Zodiac and personally visit the ship, which terrifies the rest of the team. After laying down his weapons, he convinces the officers greeting him to let him speak to the captain.

The walk to see the man in charge evokes memories of “The Hunt for Red October.” In only minutes, things turn sinister when the current officer in command (Costas Mandylor) reveals that the original captain in charge had been shot in a mutiny involving an angry sailor, Petrov (Dennis Keiffer).

Steve sees the wrapped, dead body stored in a refrigeration locker. Soon to follow is a “pebble” dropped by Petrov in the form of a slain Hawaii police officer. Danny and Steve rush to nab the espionage trader and killer, and Jerry (Jorge Garcia) returns early from medical leave, unable to resist the case of a Russian ship coming so close to home. Naturally, the conspiracy theorist had long since predicted a Russian invasion of Hawaii.

Danny and Steve get nothing useful from the Russian consulate, even after Steve calls their representative “a scumbag” and threatens to have his local mistress revealed and his credentials revoked. Steve makes another trip to talk to the acting officer on the ship, making sure he knows that the very presence of the craft is seen as “an act of aggression.” Further investigation uncovers that Petrov witnessed the murder of his parents as a young boy and lives to avenge their deaths.

What does prove to be a major break is contact traced from Petrov's stolen police cruiser to an American couple in Hawaii, the Sterlings. The team descends on the home, but Petrov has already done a bang-up job in making sure the couple can't talk. They are bound to each other and to chairs, their weighted bodies at the bottom of their pool. Junior discovers a cache of passports and victims’ identities in the home, which is rigged like a spy movie with hidden rooms. Noelani (Kimee Balmilero) uncovers information during her autopsy of Mr. Sterling that indicates that he suffered a heart attack while being questioned. Petrov wanted details.

Leads eventually trace evidence to a waiting American sleeper spy, Monica Shore (Andrea Elizabeth Sikkink), who “Hawaii Five-O” suspects is under shelter at the consulate with her daughter.

By the time Steve and Danny get to the consulate, the guards at the gate have been shot. Inside, a fierce gunfight and physical battle happen. Even using pencils, McGarrett prevails at last over Petrov. Let's hope that Alex O'Loughlin didn't personally do those fight scenes. That kind of body toll might put the star’s return for Season 9 at risk.

In the basement, “Hawaii Five-O” calls out Monica Shore and arrests her. The result is the discovery of numerous spy operations planted right on or near military bases. The spy ring is closed, and Tani (Meaghan Rath) confides in Junior regarding her disturbing discovery at Adam and Kono’s house.

Steve and Danny return to find their restaurant progressing well in the hands of professionals, who even get the liquor license.

They all pose for a picture under the “Grand opening soon” banner.

Tani feels great loyalty to Adam (Ian Anthony Dale) due to all he did to save her brother's life, and also because she saw the ruthless vengeance of his sister when they rushed to find Jessie (Christine Ko). She can’t shake the chill of hearing Adam say “she deserves much worse” of his sister. When she reveals the discovery of the gun in the drawer to Junior, she asks whether she should tell McGarrett. Junior counsels that she must, just before the last credits roll for Season 8.