Death Note is as big as anime itself. A show that has been famous for being likable, even for people that don't really watch anime, highly recommended for starters. When presentations are not needed it's time for talking specifics.
It's easy to remember the spectacular moments, the times either Light or L were cornered, the shocking reveals, however, there was one particular moment that didn't excel by its showmanship, but for its simplicity. Sometimes you don't need to put together a flashy display in order to evoke tension and thrill. That can even serve as a why to distinguish great writing from average.
Overcast
The focus is on the seventh episode of the Death Note anime adaptation titled Overcast. It starts after the encounter between Naomi Misora, Raye Penber's fiancée, and Light Yagami. This comes right after L introduced himself to the remaining members of the Japanese police force that he deemed loyal, for sticking to their tasks despite everything. Naomi, a former FBI agent that had actually worked with L in a case before, wanted to join the force and contact L after finding out about Raye's death, and in consequence, starting her own investigation. Her targets were within the few suspects he was following, and one of those was Light himself who she considered a top priority because someone with such a perfect life and behavior could only have something to hide. She was on point about her theories on how the rules to kill work for Kira.
With otherworldly luck, Light coincidentally runs into her while bringing something over to the police station. After failing on her attempt to get in contact with someone near L's circle, she starts walking back home, and Light, knowing that Naomi can pose a great threat to her plans, decides to walk with her trying to dispose of her as quickly as possible. While walking, he tries to start conversation with her with the objective of revealing her name. But she won't make it easy, giving him a fake name at first for Ryuk's amusement.
For most of the episode, the conversation keeps going on circles, Light trying to convince her that he is a part of the investigation and Naomi not trusting a word that comes out of his mouth. Eventually he finally starts gaining her trust and with her real name sends her to commit suicide. If only he didn't run into her, things could have played out vastly different and greatly tilt the scales in L's favor.
One Scenario, One Conversation
Overcast is not exactly a bottle episode, but it does resemble one in many ways. The bottle episodes, common in TV shows to produce cheap episodes that allow to redistribute the budget are often set in the same space and feature as few characters as possible. Sometimes this type of episode can give space to creativity and result in a very interesting approach, although more often than not feels like a filler that doesn't really affect the story in any way. While the use of one space and a couple of characters doesn't cut any costs for an anime, it does add a different feel to a medium characterized by the frenetic.
During almost the entire episode, the only thing that happens is Naomi and Light walking along the street closely followed by Ryuk and having a conversation. The exception comes with a few pauses that show L giving the "chosen" agents new badges and a belt with panic button. Those scenes last a total of 3-4 minutes. By this description, it could perfectly be an average episode, or even below average, since it doesn't feature much and the animation isn't great.
Tension And All-Time Closing
However, with just that, a conversation, Overcast managed to create an unparalleled tense atmosphere, even in comparison to the rest of the Death Note episodes. That can only be achieved with excellent writing, direction, and iconic performances by the voice actors. It's not just about following the story of the manga, it's how you put it into action, and how you manage to adapt it to a different medium. It's equally important to be true to the original source and know when to make changes to improve it or to adjust to the format you're working with.
The changes in the tone, the expressions of both Naomi and Light, Ryuk's nonchalant attitude as the spectator. It's one of the best interactions of the story and was executed to perfection. Even Light's thoughts and internal conversations when he gets shocked after the "Shoko Maki" alias doesn't work show his breakdown, his panicking, like no other time in Death Note. What this conversation makes you feel is unequivocally better in the anime, thanks to the great display of expressions, pace, acting, tone, and the slight intermissions in the moments of biggest tension to continue telling L's story.
The closing moments of the episode are just mind-bending. Light manages to get her driver's license to confirm her identity, and right when he writes her name next to the cause of death, she asks why he keeps looking at his watch. His response, "Oh, this? It's because I'm Kira". It doesn't matter because the effect just kicked in. The expression in her eyes as she hears this words is tragic. Naomi starts walking away, headed to a death by suicide, and one that will make impossible to find the body as specified by Light. Right at the same time, Aizawa passes by them but misses them because he was opening his umbrella as it started to snow. No cliffhangers, just a heartbreak conclusion. It was all there, in the episodes' title, a cloudy day with chances of death.