Episode 23

The Campbell twins burn through their arsenal: sinking tiles, a net that changes height, gusts of wind, even stink spray on the ball. None of it slows the Foneys, who claim the set and level the match. Desperate, Carrol signals for the big guns, and a sniper in the ducts lines up on Fiona. Loid reads the tell, tackles her out of the line of fire, and absorbs the round, then reveals to his stunned partner that it is rubber and that a bulletproof vest was under his shirt the whole time, anticipated in advance. Rather than protest the interference and endanger the prize, the agents bait shots by tracking Carrol's signals, and Loid even parries a hidden bullet fired from a ball boy's wrist, sending it into Carrol's stomach. Reading his frozen opponent, Loid slams the winning point beneath the boy's legs. Carrol tearfully admits his first taste of self-disappointment, and Loid urges him to grow into a true player; Fiona reflects that reforming enemies mid-mission is exactly why she loves him.

Victory sours quickly. Cavi withdraws Lady in the Sun from the prize catalog, citing forces beyond his control, and the agents deduce the SSS has learned of the dossier and is coming for the painting. Fiona requests to browse the collection in person, positions her bag near a counter, and stalls. Loid, disguised as Cavi's secretary, prepares the painting for the SSS handoff, and only after the security service departs with their prize does he reveal the switch: a pre-made forgery went out the door while the genuine article rode home in Fiona's bag. The secret code on the canvas goes to headquarters, where the truth deflates decades of rumor. The dreaded Zacharis Dossier is the colonel's diary guarding a hoard of actress postcards he hid from his disapproving wife; a sworn-to-secrecy musical evening for Western diplomats snowballed into legend. Sylvia counts it a win, and Loid muses that any lie serving peace is justified.

Before that debrief, Fiona's drive home detours past the park where the family is playing. Framing it as a fitness check for Operation Strix, she challenges Yor to a match, privately intending to crush her into surrendering the mother role. Yor, convinced that refusing or losing means being reported and replaced, accepts. Her first full-power serve slices the ball into pieces mid-air; her restrained second serve travels faster than sound and blows a hole through Fiona's racket. The shattered agent concedes for now, vows a future rematch through tears, and is last seen in a post-credits scene training in the mountains by swinging a boulder lashed to a stick. Yor announces her victory to Loid, receives a distracted acknowledgment, and walks home oddly subdued.

The Foneys win the Campbelldon despite a sniper, armed ball boys, and a fully rigged court, and Loid inspires Carrol Campbell to pursue tennis honestly.

Loid, disguised as the secretary, hands the SSS a forgery of Lady in the Sun while smuggling out the original in Fiona's bag.

The Zacharis Dossier proves to be a diary hiding the colonel's starlet postcard collection from his wife, not a war-starting bombshell.

Fiona challenges Yor to tennis and is annihilated by a supersonic serve, cementing Yor's place in the family while leaving her strangely deflated afterward.

The episode adapts Chapters 33 and 34, closing out the core of the Campbelldon Tennis Arc, and aired in Japan on December 10, 2022.

The manga shows Fiona looking openly upset before stepping out of her car at the park, a beat the anime softens. Conversely, the anime adds a melancholy pause once Yor reports her win to Loid, hinting she wanted praise he never gave; the moment feeds directly into her solemn expression at the episode's end and into the following episode.