The episode unfolds with Gillian Fletcham (portrayed by Saskia Strallen) making a bombshell announcement: TV's talent scout for "Go Dancing," Kevin Clifton, will descend upon Kembleford in a mere six weeks, seeking out promising contestants. With the scout's arrival looming just days away, Brenda Palmer (Ruby-May Martinwood) ramps up her dance training into overdrive. Amidst the clamor of the radio blaring, Mrs. Devine (Claudie Blakley) finally comprehends why Canon Damian Fox's (Roger May) phone calls have gone unanswered, her voice having to compete with the din. Father Brown (Mark Williams), ever the gentleman, obligingly steps aside to return the unanswered call, just as Brenda discovers she has inadvertently returned from her dance rehearsals with a stranger's bag in tow.
The atmosphere in the studio is thick with tension, especially for Derek Fletchman (Adam Rhys-Charles), as everyone strives to hone their routines to perfection. Gillian, not content with merely splashing out on a new gown, has secured a glitzy new partner—none other than Stallion Mario Cantoloni (Tom McCall). Over lunch, Brenda and Mrs. Devine's gossip about Gillian's glamorous Italian partner piques Father Brown's curiosity, prompting him to pay an unexpected visit to the studio.Mario cuts a dashing figure as a seasoned performer and a charmer among the ladies, until Father's clumsy attempt at a French conversation embarrasses him. Mrs. Highbury then endeavors to unravel Mario's tumultuous history with his native land, prompting Father Brown to inquire about Robert Highbury. Suddenly, a piercing scream pierces the air, drawing everyone's attention sharply.
Reluctantly, Inspector Sullivan (Tom Chambers) instructs Sergeant Goodfellow (John Burton) to grill Derek about Gillian's torn dress, while he tries to make amends for missing a date with Devine. Brenda complicates the situation further, and Father Brown inadvertently adds to the awkwardness by inviting Sullivan to witness the dance tryouts.
Later in the day, Father Brown learns that Gillian and Derek's mother was once a renowned ballroom dancer who sacrificed her career to nurture her children. The studio served as a testament to Gillian's devotion to her mother's legacy. As rehearsals conclude, Derek apologizes to Brenda for the unforeseen disruption and offers to dedicate extra time to her routine if she arrives early the next day.
To her astonishment, when she arrives, she finds Derek in a dazed state, smeared in blood. Father Brown scrutinizes the murder scene and notices several peculiarities. An unusual cabbage odor emanates from the body, and her mother's bracelet is conspicuously missing. Derek, found in possession of the bracelet, is promptly arrested.The enigma surrounding the vanished bracelet unfolds as Father Brown interrogates Derek at the precinct. Derek's casual mention of Gillian's peculiar demeanor prompts an exploratory venture into the studio's office. Accompanied by Brenda and Mrs. Devine, Father Brown witnesses Mrs. Highbury announcing the cancellation of the competition, citing a shortage of instructors. Before Father Brown can interject, Mrs. Devine hastily volunteers her and Brenda's help. However, he swiftly steers the conversation towards Mario.
A cleverly concealed bank statement leads Father Brown on a trail that points directly to Robert Highbury. Subsequent probing uncovers that the studio was on the brink of financial collapse due to Gillian's reckless spending habits. As the proprietor of the bank that funded the studio, Robert not only holds a personal interest but also possesses ledger entries indicating that Gillian had exploited her friendship with Mrs. Highbury for monetary benefits.
Returning to the dance studio with his newfound revelations, Father Brown discovers that Mrs. Highbury has already departed for St. Marys. Additionally, he learns that Mario's patience is equally worn thin, and Mrs. Highbury, in her haste, overlooked waxing the dance floor.
Finding Mrs. Highbury utterly engrossed in the church's floral decorations, Father Brown expresses his gratitude for her years of dedication before confronting her about sabotaging Gillian's dress. She confesses to the act of vandalism while also divulging that it was her brainchild to pen the letter to the producers of "Go Dancing."The stagnation in the case's progression prompts Father Brown to revisit the police station, where he uncovers a startling revelation: despite the absence of a name plaque, Derek stands accused of murder. Sullivan attributes this charge to Derek's fingerprints found on the trophy, coupled with a unmistakable motive.
As Father Brown heads towards the studio, he is astonished to encounter Brenda and Devine in pursuit of Mario. A brief exchange reveals that Mario has prematurely vacated his room, leaving behind a tangled mess of bedsheets. The peculiarity of this revelation sparks Father Brown's curiosity, prompting him to inquire further with Mrs. Devine about an old school photograph of Gillian that she had earlier discovered during her office search. Upon a swift glimpse at the photograph, Father Brown dashes out in a hurry to thwart Mario's departure.
Father Brown manages to hail a cab just in time to intercept Mario. Later, Mario confesses to his deception and unburdens himself of the entire truth to Father Brown, Devine, and Brenda. Throughout the conversation, he steadfastly maintains his innocence, while acknowledging that he and Gillian had struck a deal to uphold her silence. This revelation jogs Devine's memory about the showcase, and she dashes off, with Brenda hot on her heels.
Meanwhile, Brenda and Devine scramble to tie up the last-minute loose ends for the showcase, while Father Brown endeavors to prevent a potential physical altercation between Sullivan and Mario. Mario expresses contrition, ascribing his flirtations with Devine to his Mario persona. Upon grasping the significance of Mario's confession, Father Brown's gaze shifts to a nearby garden. A few moments later, Father Brown identifies the "cabbage-like" odor emanating from the body as that of Yarrow Root. He mentions that besides its pungent scent, the root can also be employed to induce miscarriages, adding an eerie depth to the unfolding scenario.
Elsewhere, Devine has secured the attention of "Go Dancing's" scout and hurries back to the studio with him in tow, as Brenda implores Mrs. Highbury to accompany her there. When Mrs. Highbury realizes that Brenda has inadvertently taken her bag from the studio, her true colors are exposed as the culprit. By the time Father Brown and Sullivan arrive on the scene, she is overwhelmed with sorrow, tears streaming down her face. After several poignant moments of confession, the essence of Gillian's murder is revealed: Mrs. Highbury's heart-wrenching inability to conceive and her悲愤-driven role in causing Gillian's forced miscarriage.
Despite the day's tumultuous events, the competition soldiers on. Derek arrives just in time to witness Brenda's routine, which captivates the scout, who nonetheless gently reminds her that "Go Dancing" is a show tailored for the elegance of ballroom dancing. As Brenda discusses the routine and the scout's feedback with Derek, she asserts that her passion for dance stems purely from joy. Derek, moved by her sincerity, vows to keep the studio's doors open and to run it with a similar spirit of joy and enthusiasm. The episode culminates in a tender moment, with Sullivan and Brenda professing their love for each other amidst a heartfelt dance routine.
