Relationships in “Wonderland,” an upcoming Korean sci-fi fantasy film, are seemingly easier to handle than in real life. Closure from death or breakups can be avoided as people are able to reconnect with their lost loved ones through the help of artificial intelligence.

Directed by Kim Tae-yong, the film features an ensemble cast composed solely of A-listers Tang Wei, Suzy, Park Bo-gum, Jung Yu-mi and Choi Woo-shik, who each play characters that deal with — or rather, dodge — grief and loss through an AI service called Wonderland that offers reincarnations via video call simulations.

The bittersweet possibility of digitally reuniting with a lost significant other or family member can offer solace — but can we say that they really exist? It’s a question that director Kim has had about video calls in general even among the living.

“I’ve always felt that the confines of human relationships have become very blurred through video calls nowadays,” he said during a press conference at CGV Yongsan in central Seoul on Thursday. “We’re able to interact with anyone, anytime, but sometimes it leaves me wondering, is the other person on the line actually there?”

Kim then took it up a notch: “What if there comes a time when we can be in contact with the dead through video calls?” And this became a eureka moment that led to “Wonderland,” his first feature film in 13 years since “Late Autumn.”

“This film is based on my own curiosity and I felt like it was my job to answer it,” he said.

But “Wonderland” doesn’t flaunt the infinite potential of AI technology or the virtual world. It’s meant to inspire viewers to think about their own interpersonal relationships, which is why Kim focused on making the plot “relatable” and “believable,” after receiving help from actual AI experts.

Tang plays Bai Li, a mother who signs herself up for Wonderland to hide her death from her young daughter. As Bai Li becomes an archaeologist in the afterlife, Tang met with actual experts in that field and bought books on the field.

“We now have more books on archaeology than on cinema at home,” joked Kim, who has been married to Tang since 2014.

It’s also the husband and wife’s second time working on a film together since first meeting on the set of “Late Autumn.” Despite some concerned reporters asking if it wasn’t troublesome to work together professionally, Kim and Tang agreed that they were compatible, thanks to both being such workaholics.

Suzy and Park are already a familiar duo who have hosted the annual Baeksang Arts Awards for several years now, but in “Wonderland” they have returned as a couple. When Park’s character, Tae-ju, falls into a coma due to an accident, Suzy’s character, Jeong-in, is desperate to stay with him through Wonderland. A problem, however, arises when Tae-ju wakes back up and isn’t entirely who he used to be due to brain damage.

There was a lot of “complex, inexplicable acting” required to play Jeong-in, with Suzy describing it as a roller coaster of emotions.

“Jeong-in would be devastated when Tae-ju becomes unconscious, and then she would be filled with joy after seeing him through Wonderland but then once again become overwhelmed with yearning after the video call ends,” she said.

Jung and Choi both play characters who work for the company behind the Wonderland service as planners. Jung’s Hae-ri is introduced as being raised by digital versions of her parents on Wonderland after they died when she was young.

Casting Jung as Hae-ri was a priority for Kim, as it reminded him of a similarly odd role she had in one of his previous films, “Family Ties” (2006), in which she played a daughter who lived with two mothers.

“Jung is an actor who never lets you down,” Kim said. “She has a way of portraying a unique role to be universally relatable.”

“Wonderland” features a special cameo by actor Gong Yoo as an addition to the star-studded lineup.

Tang recalls first meeting Gong during the pandemic in a video call.

"Even that seemed like using Wonderland,” she said. “He probably thought I had a big head because he told me he was seeing me through a large-screen monitor.”

“Wonderland” premieres on June 5.

BY SHIN MIN-HEE [shin.minhee@joongang.co.kr]