“X-Men: First Class”

Starring: James McAvoy, Michael Fassbender,… “X-Men: First Class”

Starring: James McAvoy, Michael Fassbender, Jennifer Lawrence

Director: Matthew Vaughn

Studio: Marvel Entertainment

Grade: B

The third “X-Men” film was iffy and the fourth flopped — so when the trailers for “X-Men: First Class,” a prequel to the former flicks, first appeared, fans of the original movie groaned.

But those fans might have lamented too quickly. “X-Men: First Class” breathes new life into the series with an energetic cast and an action-packed story. The plot shifts its focus from the franchise’s main characters, instead telling the tale of a newly varied group, including two of the big players from previous installments, Professor X and Magneto.

The “X-Men” series explores a world in which human mutations have created beings with special powers. Themes of prejudice and acceptance dominate throughout as mutants attempt to co-exist with normal humans, who often fear or loathe the powerful hybrids.

“First Class” focuses on the leaders of the future mutant movement as young adults living during the Cold War.

The movie departs a bit from the storyline of the “X-Men” comics, which is understandable — as so many variations exist in the comics that translating the complex stories to the screen creates headaches for directors. It’s refreshing to see filmakers take inspiration from original source material while putting their own spin on the story.

The film features the younger versions of telepath Charles Xavier (James McAvoy), later known as Professor X, and Erik Lehnsherr (Michael Fassbender), called “Magneto” because of his ability to generate and control magnetism.

“First Class” begins with the young Erik losing his mother in a concentration camp during the Holocaust. He spends the following years hunting down those responsible, seeking revenge. Meanwhile, Charles lives with Raven (Jennifer Lawrence), a shape shifter, as the pair of close friends study at Oxford.

When a CIA agent comes to Charles for help, fate brings him and Erik together during a brief fight against the film’s villain, Sebastian Shaw (Kevin Bacon) — a man from Erik’s past intent on causing nuclear war. The two then team up to track down mutants around the world as they search for potential help against the enemy.

Throughout the film, Charles believes that the good he and his fellow mutants can do for mankind will outweigh the bad. Erik, doubtful, plows ahead with plans of revenge on Shaw.

For fans of the franchise, it’s blatantly obvious during the film what the final outcome will be — Professor X and Magneto as enemies. Despite this, Matthew Vaughn spins a tale interesting enough to keep all viewers entertained during the journey.

The characters are rounded overall: Their personalities develop over time, and they deliver some humor along the way. They interact well as comrades and also gradually exhibit the fear and betrayal that is inevitable in the story.

One of the best — and worst — parts of this film are the attempts to connect it with the other parts of the franchise, such as showing the design for the ship used in previous movies. They don’t always work and will sometimes leave fans scratching their heads. But the film is generally tied together well andfeatures cameos from a few recognizable and much-loved characters — including one vulgar appearance from the universal favorite badass of the series.

This film never quite succeeds in making the setting feel like the 1960s: The characters feel, dress and act too modern to pull the time period off. But this is a minor pitfall. There are times when the performances, too, lack believability because of those too-modern touches,  but that’s quickly forgotten during the riveting final battle.

Overall, this is a slightly flawed but fun addition to a popular series, and it certainly signals an upswing from the last two “X-Men” movies.