The opening scene of The Crystal Cuckoo's first episode finds us in 2005, where a cop named Miguel is drenched in blood. His young son, Juan, catches a glimpse of him and Miguel whispers for him to keep it a secret. As Juan drifts off to sleep, Miguel's composure shatters, revealing a depth of emotion beneath the surface.
Fast forward to 2022, where Clara, a first-year resident, experiences a heart attack in the ER. She awakens a month later with a new lease on life, courtesy of a heart transplant. Her curiosity piqued about her donor, Clara is reminded by her friend Moni that revealing the donor's identity is taboo.
In 2004, Juan embarks on a picnic with his brother Carlos and their parents, Miguel and Marta. As they enjoy their day, a fire breaks out, and Miguel rushes to ensure it doesn't spread to Gabriel's house. His partner and Gabriel's nephew, Rafa, panic as Aunt Luisa remains inside. Despite their best efforts, they are unable to save her.
Miguel's righteousness shines through as he confronts Ribo, the town drunk, about hitting his wife. He then questions Gabriel, who reveals Luisa was a troubled woman and the couple was temporarily separated. Gabriel's fascination with cuckoos and their parasitic nature is evident in his demeanor.
In 2023, Clara pushes her new heart to its limits, determined to uncover her donor's identity. With Moni by her side, she delves into the mystery and discovers that the heart belonged to Carlos. She stumbles upon Marta's restaurant and finds a phone number. Initially reluctant to talk, Marta is eventually drawn into reminiscing about the good times with her family. She invites Clara to Carlos' memorial to help scatter his ashes. While Moni finds it peculiar, Clara agrees, eager to learn more about Carlos and her newfound connection to him.
As Clara's arrival neared, Marta's enthusiasm was palpable, practically welcoming her with open arms, eager to know every detail of Clara's life. Her warmth was so overpowering that Clara found herself hesitating at the threshold of Marta's home, questioning if she had accidentally interrupted a secret invitation to an intimate gathering. Marta's insistence on Clara extending her stay until the weekend's drum festival was almost a subtle push, an unspoken plea to rekindle a past that seemed to have faded away.
We are reminded of Carlos, whose life had been cut short by a brittle bone disease that claimed him in a tragic accident. Juan, on the other hand, had taken up the mantle of a cop, his eyes always scanning the horizon for clues, especially when it came to Clara. Through Rafa, the whispered truths of Miguel's disappearance in 2005 echoed like a ghostly refrain, warning Clara against unraveling the past and urging the family to move on.
Flashing back to 2005, Marta's frantic call to Rafa about Miguel's disappearance was followed by an ominous mention of Silvia Luna, a name that hinted at a forbidden romance that might have led Miguel astray. A cop's questioning eyes bore into Juan, but he stood firm, not letting any trace of the bloody night slip from his lips.
Returning to the present year of 2023, Clara's curiosity led her to explore the house, where she stumbled upon a notebook filled with spiraled doodles, a testament to a mind that had once been occupied by thoughts as intricate as the patterns on the pages. Outside, a woman strolled with her two children, her attention diverted by her older child's antics, leaving her infant daughter, Manuela, unattended and vanishing into thin air.
