Actors Han Hyo-joo, left, and Ju Ji-hoon pose during the press conference for the series, "Blood Free," at Conrad Seoul in Yeongdeungpo District, Seoul, Monday. Courtesy of Disney+

Actor Han Hyo-joo is returning with another Disney+ original series, "Blood Free," after playing the lead role in the platform's smash-hit series "Moving" last year.

"The script [for this series] was a brilliant story that's [aptly timed]. I enjoyed it so much that I wrote a diary after getting the script," Han said during a press conference for the series at Conrad Seoul hotel in southern Seoul's Yeongdeungpo District, Monday.

"I was so happy to finally have such a good script coming to me. The script made my heart pound that much."

The sci-fi thriller series, scheduled to roll out on Wednesday, follows a biotech company CEO, Yoon Ja-yu (Han), who commercialized lab-grown meat.

Trailblazing in the new field, she has become a high-profile figure, yet at the same time, constantly faces threats, leading her to hire a personal bodyguard, Woo Chae-woon (Ju Ji-hoon).

When she and Woo investigate a series of mysterious deaths around them, the two come together to uncover the truth and the figure behind the incidents.

The series, which is expected to offer a thought-provoking look at the potential consequences of biotechnological advancements, is scripted by popular writer Lee Soo-yeon, who is known for the 2017 hit thriller series "Stranger," and directed by Park Chul-hwan, who previously led the Disney+ original series "Grid" (2022).

A scene from the series "Blood Free" / Courtesy of Disney+

Han said she tried to portray her character as restrained and enigmatic.

"I wanted Yoon to appear mysterious when you first see her, making it difficult to tell whether she is good or bad. Since she doesn't really show emotions overtly, I put a lot of thought into how to add variation and expressiveness within her emotionless face," she said.

"In terms of tone, I also made efforts to ... create a character [who is] like a dry, fallen leaf, trying not to reveal emotions."

Joo plays a former soldier who approaches Yoon with a hidden motive.

"Woo is a soldier-turned-bodyguard. He was assigned to protect the president when they were hit by a terrorist attack. He is undercover to find the mastermind behind the attack," Joo said.

"I found it challenging to set the details as the setting is the near future. I thought he needed to be grounded and realistic to make the story convincing and believable to viewers."

Park shared that as the series is set in the near future, he tried to make it as realistic as possible despite the sci-fi elements.

"When we were shooting, I didn't expect artificial intelligence (AI) to become such a heated topic. I just had in mind not to make it look awkward," he said.

"There are technologies like cell cultivation and AI already in real life. So I researched the actual companies to bring out the reality. Sci-fi is one aspect of the series, but when you watch it, there is more that unravels from realistic stories."