Wanted to rewatch a shorter case and checked this out pretty thoroughly - there is some unorthodox writing used to introduce a new character in this. The case starts with two lovers partying for the wedding that would be held the very next day with the groom's, Banba's, old classmates that including Kogoro being present, and the bride's, Kamon's, party would be held at a later point. That is also used to foreshadow the part that Amuro was hired, but anyway.
The aesthetics are pretty balanced, it's technically a party at an Italian restaurant but the heavy rain kind of pulls the mood to a more balanced state and it's basically just Kogoro, Conan and Ran eating at their table while others have fun. The moment Kamon leaves the restaurant to go to the nail salon Gosho drops a pretty cool hint with them both saying to each other that if the other would cheat, there'll be a hell to pay, and when they leave the moment with their kiss is actually really powerful after you finish the case. Normally you'd not see that in real-time, but in a flashback. Right after Kamon leaves Banba starts flirting with the other girls and it's pretty funny to see the mention of how he's exactly like Kogoro.
Then there's the scene with Banba's two cellphones, which is pretty cool as they don't get focused on, you kind of understand why he has another phone if you follow the case. Banba gets a phone call, talks aggressively and then shuts the call and after that goes to the bathroom. Then a man with sunglasses comes out of the bathroom and goes to the table, calls the waiter nearby to give him an order to get bourbon on rocks. Then a drunk Banba comes and hits the waiter, and the sunglasses man asks him if he remembers the order, which the waiter does.
Throughout the night Banba acts really aggressively and keeps shouting at the waiter, even hurts himself by trying to attack the waiter as the glass breaks on the floor. Then he calls Kamon who tells him sayonara on the phone and her call cuts. As Kogoro and the rest look out the nearby window, they see a flaming car, and the scene quickly transitions to when Inspector Megure and the rest are already on the scene. Megure himself was honestly pretty impressive in this case as he immediately tracked down in a flash of all the things that you'd try to figure out a culprit would be doing to trick the police in a case. It's actually not easy to see but after paying attention I really like that, of course it wouldn't lead to finding the culprit but it was never presented in an impressive way in the first place, he just does stuff like pointing out possibilities of tricks these characters would be using.
Later we learn that it's actually been an adultery investigation and the sunglasses man introduces himself as detective Haruka Sanji who has been investigating Kamon because he was hired by Banba who was suspicious that Kamon had a secret lover. Later it's revealed that Haruka came, went to the bathroom to tell that he might know who the lover is, then came back to confirm it, and the part with Banba hitting the waiter was never focused on in the explanations either but you can easily see what's up when you connect it to Haruka re-asking his order.
Then on the other end of the spectrum we have the waiter, who introduces himself as Amuro Tooru, a detective hired by Kamon to investigate Banba on whether or not he has a secret lover. Kamon leaving for the nail salon was planned and Amuro being a waiter at the restaurant was technically planned as Amuro told Kamon to tell Banba that they should hold the wedding celebration party at the Italian restaurant where he worked part-time... Amuro deliberately throws the cake on Banba's clothes at the beginning of the case to make him look dirtier so that he won't go flirting with the girls when Kamon leaves, but Amuro's plan fails and Banba doesn't care. Banba's aggressive actions towards Amuro are written in sort of subtle way despite being so clear as Amuro is the man Kamon has been meeting, and the case focuses on that at times, like with Banba claiming that Amuro visited his house and used his hairbrush. The timing of Banba's actions become more frequent after Haruka confirms Amuro's voice being the voice of the 'lover.' Also I have to note that it's interesting to see Amuro play a part in the death of the victim in this case, since if Amuro hadn't investigated on Banba's and Kamon's past and told her his findings, she'd still be alive.
So yeah the case is about an awkward circle of two detectives being hired to investigate each other of adultery by a suspecting bride and groom who - due to their sad circumstances - are basically capable of thinking the exact same way the other is, and even knowing their thoughts.