Martial arts mayhem and family dynamics are the building blocks of The LEGO Ninjago Movie, the third in the animated franchise.

“Every LEGO movie is different,” says producer Dan Lin when STACK catches up with him and the film’s voice cast at Comic-Con. “The first one is an action-adventure, the second was a superhero movie, and this one is our version of a martial arts/giant robot movie.

“I think the challenge is how do we constantly innovate with each movie. How do we make it feel different and cinematic, with the same LEGO Movie tone?” he continues. “We’ve brought some new live-action elements into this movie, and we have some organic elements – real grass, water, trees – as well as a great comedy cast. It’s really different and the most beautiful looking LEGO Movie we’ve done so far.”

The LEGO Ninjago Movie is based on an original LEGO property that also inspired the TV show Ninjago: Masters of Spinjitzu, and the design of the mini-figures from the TV show characters have been updated for the movie.

The story involves a team of six young ninjas – voiced by Dave Franco, Kumail Nanjiani, Michael Peña, Zach Woods, Abbi Jacobson and Fred Armisen – who fight to defend their island home of Ninjago from the evil Lord Garmadon (Justin Theroux). And in true LEGO Movie tradition, the group learns a few life lessons along the way, whilst battling giant robots, flying on dragons, and executing some wicked martial arts moves.

“It’s really about empathy, to learn to love others before you love yourself,” says Lin. “In this case there’s a big rivalry between Dave’s character, Lloyd, and Garmadon; Lloyd is very upset that his dad is the villain of the movie and taking over the town. It’s during a road trip that he learns what’s loveable about his dad.

“All the LEGO Movies are about family, and told in a different way. They look simple, but it’s pretty sophisticated how we try to have a good message at the end. Family dynamics is what we want to reflect in the movies as well.”

With a great ensemble cast voicing these heroes and villain, how does a bunch of seasoned actors prepare to play LEGO characters?

“We went to LEGOLAND for a couple of months just for research,“ jokes Franco, with Nanjiani adding, “I keep a bunch of LEGO under my pillow every night to get into character.”

One star absent from the Comic-Con group is the legendary Jackie Chan, who voices the ninjas’ Sensei, and Lin reveals that the martial arts master brought in his stunt team to act as doubles for each of the characters.

“When you see the martial arts in the movie, they did all the stunts, and we animated against all that action. There was wirework for the huge fights between Justin and Jackie’s character. It sounds crazy and it’s the first time we ever did that.”

“It feels so unnecessary,” quips Nanjiani.

The LEGO Ninjago Movie is in cinemas on September 21