THE WOLVERINE (Rated PG-13)

Hugh Jackman returns as the mutant hero, the titular character in “The Wolverine.” The movie raises two questions: Why is he in Japan? Why does he still sport mutton chops?

When he’s not baring his adamantium claws, Jackman’s Wolverine is known as Logan. In what is the sixth film (counting spinoffs) of the franchise, Logan is first spotted looking like a homeless mountain man in the Alaskan wild, or maybe it’s the Yukon. Whatever, it’s some place cold and uninviting.

Living like a recluse in a cave, Logan communes with nature, even managing a peaceful coexistence with a grizzly bear companion. His solitary existence is disturbed by the appearance of reckless hunters bent on snagging a large, shaggy-haired ursine trophy.

Confronting the repugnant hunters at the town saloon, Logan reverts to his old superpowers to ward off his foes, drawing attention from the enigmatic Yukio (Rila Fukushima), who entices him to Japan. So we have the answer to the first question.

Memories of World War II are fresh in Logan’s mind, as he remembers, while interned in a POW camp, saving the life of a young Japanese soldier during the atomic bombing of Nagasaki, and thereby revealing his miraculous self-healing powers.

Shifting to the present day, Logan has not aged, but the soldier he rescued, Yashida (Haruhiko Yamanouchi), is an elderly, extremely wealthy industrialist, now confined to his deathbed, wistfully hoping for immortality.

Logan’s Wolverine, who does not age, possibly holds the key to a life without end, hence the interest by Yashida and assorted shadowy, mysterious figures, obviously connected to the Yakuza, to Logan’s secret.

Lured by the curious Yukio to Tokyo, Logan ends up getting a scrubbing and makeover from geisha girls, but he keeps the mutton-chopped sideburns. The answer to the second question remains elusive and unknowable.

Dutifully paying his respects to the dying Yashida, Logan discovers that the industrialist’s granddaughter Mariko (Tao Akamoto) stands to inherit his fortune, and as a result, her life is in serious danger.

For one thing, Mariko’s father is a ruthless tycoon who is apparently involved with sinister forces that seek to take control, by force if necessary, of the Yashida financial empire.

A spectacular fight sequence with ninja warriors at Yashida’s funeral service causes Logan and Mariko to go on the run, even hiding out for a time at a seedy hotel that caters to customers renting rooms by the hour.

Meanwhile, Logan is undergoing an existential crisis, evidenced by the frequent dream sequences in which his former lover, Jean Grey (Famke Janssen), a fellow mutant that he had to kill, reminds him of misfortune and tragedy.

More than troubling dreams are at work. Logan is also consumed with thoughts that his immortality is a curse and a burden that hinder his ability to live a normal life, a thought more pressing now that his romantic feelings for Mariko have taken hold.

Due to other strange things going on, Wolverine finds his physical strength ebbing away, his superpowers gradually dwindling and his immediate ability to heal from all wounds no longer a given.

But before falling into a state of impaired faculties, Wolverine manages a spectacular fight to the death on top of a speeding bullet train with a Yakuza assassin.

With the train hurtling along the tracks and through tunnels at a speed of 300 miles per hour, the rooftop battle is skillfully staged and stunning for its heart-pounding suspense. This could be the film’s best action moment.

Not so fine is the climactic battle scene inside Yashida’s mountainous lair, where Wolverine must fight a giant robot. We’ve seen enough of this in films like “Pacific Rim,” and, well, others I have already forgotten.

“The Wolverine” is filled with plenty of faceless villains, mostly ninja types who are fairly well disguised in their black robes and masks.

The most interesting bad guy is actually a femme fatale (Svetlana Khodchenkova), the blonde nurse who tends to Yashida but has a secret agenda. Though she is attractive, one would be advised not to kiss her.

Though it may not be saying much, “The Wolverine,” even when it falters at the end, is one of the better superhero movies of the summer. That’s mostly a credit to Hugh Jackman’s nuanced performance.

A word to the wise: Be sure to stay for the credits. The future of the franchise hangs in the balance with a breathless teaser.

Tim Riley writes film and television reviews for Lake County News.