Episode 4 of Constellation kicks off with Alice and Magnus trekking through the serene yet frigid Swedish woods, their footprints cutting through the pristine snow. As they near a secluded house, Magnus reassures Alice that they won't encounter 'her' again, a note of finality in his voice.
Back in the present, Jo is treated to a delightful surprise - a belated Christmas and birthday celebration hosted by Magnus and Alice. Over a cozy dinner, Magnus broaches the topic of their past, reminding Jo of how things stood before her departure. He mentions that she avoided his gaze when she left, but Jo's recollection differs.
The next morning, Jo awakes from a nightmarish slumber, her heart still racing. She gathers her composure and heads to the European Space Agency, where she's greeted with a warm round of applause. As the evening sets in, Jo raises the unresolved issues with Magnus once again. He confesses to harboring suspicions about her alleged affair with Frederic and reveals that he too had a fleeting encounter, sharing a kiss with another. This revelation stirs up a mix of emotions in Jo, but their conversation is abruptly interrupted as Alice calls Magnus away.
Meanwhile, Henry is busy scribbling notes in his office, lost in his thoughts. Elsewhere, Bud stirs from his slumber on the ship, only to be greeted by a commotion caused by the unexpected death of the debate host. In another corner of the world, Michaela calls Henry with dire news - the CAL project is being shut down due to its apparent lack of progress.
In the midst of her therapy session, Jo confesses to her therapist that her memories are clouded and distorted. She mentions the presence of a piano in the house, yet she never plays it. The therapist listens intently and diagnoses Jo with PTSD, suggesting that Lithium might help stabilize her emotions. Jo reacts with alarm, fearing that such a diagnosis could potentially end her career.
As her session draws to a close, Henry approaches her, eager to discuss her research. He shows her the CAL and delves into the profound effects of space travel on the human mind. He shares stories of hallucinations experienced by pilots and astronauts, painting a vivid picture of the challenges they face. As the CAL hums in the background, Jo suddenly feels a sharp pain in her left eye. She turns her gaze towards the reactor, a sense of unease creeping over her.
On the vast sea, Bud dialed his daughter Connie's number with a heavy heart. His voice quivered as he confessed that things were not going according to plan. He desperately desired to connect with someone, but Connie, unimpressed, dismissed his concerns, urging him to take his medication.
Meanwhile, within the hallowed halls of the school, Alice's teacher confided to Magnus and Jo about the girl's perplexing habit of hiding in cupboards. She speculated that Alice must feel estranged from her mother, a sentiment that irked Jo as Magnus nodded in agreement.
Back at their abode, Jo stumbled upon Alice, hidden away in a cupboard, her necklace dangling from the door handle. She engaged in a heartfelt conversation with Alice, who confessed that she had hoped for a different reunion with Jo.
Elsewhere, Henry engaged in a profound discussion with Professor Louis regarding the CAL. He revealed that the machine had detected a remarkable state where a particle existed in two states simultaneously, hinting at a portal to a parallel universe. However, Louis remained skeptical. Henry pondered if the experiment was having an unseen impact on him, altering his brain chemistry.
Within the cozy confines of their home, Jo attempted to play the piano, seemingly mastering its intricacies. Suddenly, she halted, her gaze fixated on her fingers. Meanwhile, Agent Bright from the FBI interrogated Bud about the missing debate host, but Bud skillfully deflected suspicion with a series of clever excuses.
Later, Jo compared the contents of her Lithium tablets with the vitamin tablets she had been prescribed upon her return to Earth. She ventured to the ESA, where a sophisticated machine confirmed her suspicions - both were, in fact, Lithium. Intrigued, she delved into the office database and discovered a startling trend: astronauts who had experienced hallucinations had all been prescribed these tablets, including Henry Caldera.
Just then, two men entered the office, busily packing items into boxes. Strangely, they seemed oblivious to Jo's presence. The light cast a different hue from their perspective, and in a blink of an eye, they vanished into thin air, leaving Jo bewildered and alone.
Jo ventures into Henry's office, where an eerie sight awaits her. Henry appears to be engaged in a conversation with his mirror image, a figure that strikingly resembles Bud. His cryptic comment about curiosity lingers in the air as Jo hurriedly departs.
Later, Frederic unexpectedly appears in Jo's office, his words spilling out in a torrent of revelations. He speaks of their secret plans, of a life together, even of leaving to pursue their careers independently. The revelation stuns Jo, who stares blankly, unable to recall any of it.
While delivering a lecture to Alice's class, Jo's composure suddenly shatters. She turns to Magnus, her voice loud and urgent, demanding to know if Sara is the woman he had encountered. The question hangs in the air, awkward and tense, before Jo storms out, her car narrowly avoiding disaster on the way home. Her hand presses against her left eye, a telltale sign of pain.
Back at their home, Frederic confides in Magnus, revealing that Jo needs rehabilitation for the burnout she's experiencing as an astronaut. He confesses further, admitting to a past affair with Jo. As Frederic's words echo in the room, Jo enters, her expression blank. She denies any memory of the affair, sending Frederic away with a cold dismissal. Yet Magnus remains unconvinced, his suspicions deepening.
Meanwhile, a mysterious package arrives for Jo, sent from a marine observatory in Denmark. Inside are two tapes, their contents a mystery. As she listens, Jo's face registers shock. Her own voice, clear and distinct, reaches out from the tapes, trying desperately to make contact with the ISS. The second tape is older, dating back to 1967, and records the chilling sounds of a space accident, a woman's voice echoing in the void.
Elsewhere, Alice awakes to a surreal scene. Descending the stairs, she finds her living room transformed into a funeral parlor, filled with strangers dressed in black. Among them, she spots another Alice, dressed identically in mourning attire. A scream escapes her lips as the vision fades, and Magnus rushes to her side, guiding her into a cupboard where she feels safe. He whispers that she's afraid of Jo, his words heavy with concern.
The tension mounts as Jo and Magnus argue, their voices rising. Magnus resolves to call Frederic and arrange for Jo to be sent to rehab. But Jo is unyielding, lunging for the phone. In the struggle, Magnus falls, his head colliding with a table as he tumbles to the ground.
The final scene of Constellation Episode 4 is a haunting image. It reveals the painting from the remote cabin in Sweden, a nightmarish portrait of a skeletal creature that seems to stare back with hollow eyes, a silent witness to the unfolding drama.
