This is the best volume, and my favorite of the series, so far.
First, it introduced a new character in Agent Nightfall, a "tsuntsun" who has a massive crush on Loid Forger, aka Twilight. Some might say she's a "tsundere", but the only time she's "dere", is in her internal monologue when she's fantasizing about Loid. Thus, she's all "tsun", a "tsuntsun".
Second, the main storyline in this collection is a classic shonen manga staple, a battle tournament arc. Actually, it is two shonen tropes in one because it is a sports battle tournament, as Twilight and Nightfall enter an underground tennis tournament for a weekend mission.
Third, I just love the retro vibe of the character designs and their sports attire. Since the duo are on an undercover mission, Loid channels his inner Ivan Lendl as a disguise, complete with the long hair in a headband and a wooden racket. As for Nightfall, it appears she has Steffi Graf as her design inspiration.
The next few standalone chapters serve as epilogues of sorts when the main arc ends, and it making a seamless transition to move the overall plot (Operation Styx), forward.
This is a really funny volume. There are times I just break out laughing in chained bursts. Perfect reading anytime, especially in a pandemic, and in a quarantine. It deserves all 5 stars.