EXCLUSIVE: Inside John Lennon and Yoko Ono's Secret Fight to Find Missing Daughter — With New Documentary Lifting Lid on Harrowing Kidnapping Case That Still Haunts Tragic Beatles Icon's Widow

A harrowing new documentary sheds light on the painful abduction of Yoko Ono's daughter by her father and the years she and John Lennon spent trying to track her down.

RadarOnline.com can reveal the film One To One: John & Yoko reveals the tumultuous and costly saga that haunted Lennon and Ono for decades – and which still haunts the Beatles icon's aging widow.

The film chronicles Yoko's relentless pursuit to reunite with her daughter, Kyoko, whom her first husband, Anthony Cox, abducted in 1971, resulting in a staggering $2 million spent on the chase.

In a poignant reflection from a 2003 interview, Ono expressed the deep pain of loss, stating: "Losing my daughter was a very serious pain. There was always some empty space in my heart."

RadarOnline.com can now reveal details of the tug-of-love that stretched over decades.

Ono married Cox in the summer of 1963 and welcomed Kyoko into the world just two months later.

As she navigated the delicate balance of motherhood and her artistic endeavors, the couple's relationship evolved into a creative partnership.

By the time Lennon first attended one of Yoko’s solo exhibitions in 1966, their marriage was already on the rocks.

Just two years later, both Ono and Lennon had separated from their partners and embarked on a romantic relationship.

Initially, the parting was civil, the couple even entertained the notion of forming a band with Cox's new girlfriend, Melinda Kendall. However, tensions escalated dramatically following a car accident involving Lennon while on vacation with Ono and their son, Sean.

The incident led to a five-day hospital stay, further complicating the dynamics of their blended family.

With no formal custody arrangement in place, Cox grew increasingly anxious, insisting on being present during Lennon and Ono's visits with Kyoko.

By 1971, he had taken drastic measures, abducting Kyoko and fleeing to Majorca, where he was studying Transcendental Meditation.

But when Lennon and Ono traveled there to locate them, Cox accused them of attempting to kidnap Kyoko, resulting in their brief arrest.

Following the confrontation, he relocated to the United States, prompting a bitter custody battle.

Despite a court decision granting Ono and Lennon custody on the condition they remain in the U.S., Cox once again fled with Kyoko, effectively severing ties with her mother for 23 years.

Living in fear of arrest, Cox adopted false identities while hiding as a member of a little-known religious organization, The Church of the Living Word.

Reflecting on her childhood, Kyoko, now 61, recounted in 2003: "Mom says (now) that she wouldn't have put him in jail, but as a child, I didn't know what was going to happen. I was protective. My dad had a lot of problems, but I was his only kid. It was very painful losing my mom, but I love my dad too."

Ono, heartbroken over Kyoko's absence, sought various means to reach out, including a heartfelt appeal on The Mike Douglas Show in 1972, where she said: "If Kyoko is watching, I'd like you to know that I love you, and if you miss me at all, you could try to reach me."

Tragically, Lennon never had the opportunity to reunite with Kyoko before his untimely death in 1980.

Following his murder, Ono received a telegram from Cox and Kyoko, but it offered no contact information, leaving a chapter of sorrow and longing in their lives. It was 1994 before Kyoko, then in her 30s and living as an artist in Colorado, reached out to her mother for the first healing conversation between the pair.

A spokesperson for Ono, 92, told New York Magazine in 1997 Kyoko visited "all the time and they have a very nice relationship" with Ono – adding: "They speak every day."