The storyline exploring how DI Costello manipulates Lisa while pulling Becky into a devastating and dangerous plotline on Coronation Street stands as one of the most psychologically intense and emotionally unsettling arcs the soap has delivered in years. Costello, already known for his cold calculation and chilling ability to control people, takes his manipulation tactics to new and disturbing heights as he strategically targets Lisa, recognizing her vulnerabilities and emotional blind spots with terrifying precision. From the moment he first locks eyes with her, it becomes clear he sees something he can exploit—a weakness she has tried desperately to hide, a longing for stability, validation, and safety that makes her an easy mark for a man as cunning as he is morally bankrupt. He approaches her slowly, subtly, weaving himself into her life not through force but through carefully crafted kindness, supportive words, and an uncanny ability to appear at moments when she feels most alone. Lisa, still shaken by past trauma and trying to rebuild her sense of trust, becomes increasingly susceptible to the comforting narrative he is fabricating for her benefit—and his own control.

As days pass, Costello’s manipulation deepens with disturbing effectiveness. He plays the role of a protector, a confidant, even a mentor, all while planting seeds of doubt inside Lisa’s mind about the people around her, especially those who care about her most. He isolates her psychologically before she even realizes what is happening, making her question her relationships, her memories, and even her instincts. His tone remains calm, calculated, reassuring—never raising suspicion, never making a move bold enough to expose his intentions. Yet every conversation, every gesture, every moment of feigned empathy is designed to mold her into a pawn. Lisa, unaware of the larger plan, slowly begins to second-guess herself, leaning dangerously closer to Costello for guidance. She feels seen and understood in a way she has not felt in years, not realizing that the man she believes is supporting her is meticulously dismantling her confidence from the inside out.

Becky, however, begins to sense something is wrong long before Lisa does. She notices the sudden shifts in Lisa’s behavior—the hesitations, the defensive reactions, the unexplained loyalty Lisa develops toward Costello that seems out of character. At first, Becky assumes Lisa is simply stressed, overwhelmed, or struggling through something she doesn’t yet feel comfortable admitting. But soon the pattern becomes undeniable: Lisa is not acting freely. Something—or someone—is rewiring her thoughts. Becky’s growing alarm becomes the emotional core of the storyline, highlighting her fierce loyalty and protective instincts. She tries to speak to Lisa, reach out, reason with her, but each time she does, Costello’s influence has already laid the groundwork for resistance. Lisa begins to perceive Becky’s concern not as love but as intrusion, a direct result of the psychological conditioning Costello has been carefully implementing.

Costello escalates his manipulation by positioning Becky as the enemy, telling Lisa subtle half-truths and carefully constructed lies that create a division between the two women. He frames Becky as unstable, jealous, or controlling—whatever narrative best aligns with the emotional vulnerabilities Lisa carries. He reinforces the idea that Becky is trying to stop her from growing or becoming independent. Lisa, already emotionally fragile, internalizes these suggestions until she begins to believe Costello’s version of events over her own memories. The more she distances herself from Becky, the deeper she falls under Costello’s spell, leaving Becky heartbroken, terrified, and increasingly desperate to pull her friend back before she is consumed entirely.

What makes the storyline especially powerful is how it shows Costello’s manipulation as a slow, suffocating process rather than an overt act of villainy. He never needs to raise his voice or make threats. His cruelty comes disguised as support. He uses Lisa’s past pain as a roadmap, navigating her emotional scars with surgical precision, exploiting every wound, every insecurity, every regret she has ever confessed. He studies her fears the way a detective studies evidence, each detail becoming a tool in his psychological arsenal. He does this not because he cares about Lisa, but because breaking her down serves his larger agenda—a plot in which Lisa becomes both a shield and a weapon. And Becky, whom he identifies early as the biggest threat to his control, must be neutralized through Lisa’s growing mistrust.

As Becky digs deeper into Costello’s behavior, she begins uncovering truths that shake her to her core. She learns about his past victims, his patterns of emotional manipulation, his ability to destroy lives while appearing completely untouchable. But the most devastating discovery is realizing Lisa has been chosen specifically because she fits the exact psychological profile Costello preys on. Becky becomes determined to save Lisa, even if it means putting herself directly in Costello’s line of fire. The tension escalates as Becky tries to gather evidence, confront Costello indirectly, and warn others about what is happening. Every step she takes, however, endangers her further, because Costello is always one step ahead, watching, listening, anticipating her moves with chilling accuracy.

The breaking point comes when Costello forces Lisa into an “unthinkable choice”—a choice crafted entirely by his manipulation, designed to test the limits of her loyalty and push her to sever the one bond strong enough to free her from his influence: her connection to Becky. The emotional weight of this moment becomes one of the storyline’s most gripping elements, as viewers watch Lisa struggle between the reality she once knew and the poisonous version Costello has constructed for her. Becky, heartbroken but unwavering, refuses to give up on her friend, even as Lisa stands at the precipice of a decision that could destroy both their lives.

Through Costello’s chilling psychological warfare, Lisa’s heartbreaking vulnerability, and Becky’s fierce determination, the storyline becomes a raw exploration of manipulation, loyalty, trauma, and the devastating consequences of unchecked power. It exposes how easily trust can be weaponized, how quickly someone can lose themselves in the presence of a skilled manipulator, and how far true friendship will go to fight for someone slipping away. As Costello’s plot tightens its grip, the stakes rise to unbearable heights, promising a confrontation that could change all three characters forever.