Bomb

Bomb (爆弾, Bakudan) is the fifth chapter of volume four and thirtieth chapter of the Death Note manga series.

Plot
Light hugs Misa but his real plans for her are far from affectionate. He intends to use her and her Shinigami Eyes in order to kill L and the rest of the Kira Investigation Team and then kill her as well! Since she knows who Kira is, she could be a liability if he does not get rid of her soon.

Misa then asks if she can meet Light's Shinigami. Light asks her to turn her back to him first. Since he does not want her to know all his secrets or resources, he discretely takes a piece of the Death Note from his wallet. He gives Misa this piece of paper and she can now see Ryuk. Misa starts addressing Light by his given name. He is rather surprised by this informal way of address, given the fact that they have only just met and Misa is acting as if they are already lovers, but accepts it.

Meanwhile, at the Kira Investigation Team HQ, L is going through all the video footage taken at Aoyama on the day the Second Kira saw the original Kira in the hope of seeing someone (the Second Kira) acting suspiciously around Light. Since Light was also being investigated by FBI agent Raye Penber at the time of his death, L has now decided that he is the main suspect. Light's father, Soichiro Yagami is speechless.

Penber was also investigating the family of NPA Deputy-Director Koreyoshi Kitamura who are still being checked out by Mogi. L tells Soichiro that the Kitamuras are no longer suspects and wants Mogi to tail Light instead since Light does not know him. Soichiro grudgingly passes on the instruction.

At the Yagami house, Misa explains to Light how a Shinigami can die if they deliberately prevent the death of a human they care for. Neither Light nor Ryuk can imagine Ryuk doing something like that. Misa then explains the extent of the power of her Shinigami Eyes and how she can see a person's name and life expectancy even by looking at old photos or video footage. She also has to see a person's full face in order to see their details. She draws some illustrations in order to demonstrate the method. Light leans over her and admits to be impressed by her explanations, but then pulls himself together. He intends to kill this girl so he must not develop feelings for her and ruin his plans.

Light then tells Misa to make a final Kira tape which will inform the police that the Second Kira is accepting the advice given in their appeal on TV and will not try to meet Kira. However, the Second Kira will seek approval by killing other criminals and will also share the power with others. The final part is designed to panic the detectives: If they think that Kira's powers can be spread to others this will increase the pressure and affect their morale. He also tells her that if she’s ever caught, she must never mention anything about Light, the Death Notes or the Shinigamis to the police.

Misa agrees to all this but also requests that they meet regularly, with at least one date per week. Light tells her that this is impossible: He is already under suspicion by L and they are acquainted. Although L has no hard evidence that Light is Kira, he still has suspicions and thus is being cautious—keeping his real name a secret and preventing anyone from taking his photo, even with a cellphone. What's more, if Misa comes to L's attention and is identified as the Second Kira, her link to Light could prove disastrous for both of them. Light might have to see Misa from time to time in order to formulate plans, but he insist that, in order that their meetings do not stand out, he will have to see other girls.

Misa is outraged by this last announcement and even threatens to kill the other girls. Light insists that they must tread carefully in order to create a better world which will be free of crime, but Misa doesn't care for the world so long as she has Light to herself, having fallen in love with him at first sight. Exasperated, Light reminds her that he has both the Death Notes and will kill her is she does not co-operate, but then Rem suddenly speaks out, threatening to kill Light if any harm comes to Misa!

Rem is aware of Misa's life expectancy. If Light should try anything to shorten it then Rem will kill him, even though Rem herself will die since she is protecting someone she cares for.

Light is horrified, but before he can say anything else his mother arrives to remind them that it is late and that Misa ought to make a move before she misses the last train. As Misa leaves, Sachiko tells her son to escort her to the station. Light cannot afford to be seen with Misa right now and gives her a hard but discreet look. Misa takes the hint and leaves on her own—with the invisible Rem.

Rem's threat has come like a bombshell to Light. Now he cannot kill Misa but must also hide their relationship and protect her from the police. Things couldn't be worse.

Conception
Ohba said that the chapter title "Bomb," related to how keeping Misa around Light was "like holding on to a bomb" since Misa knows Light's true identity. Ohba also said that Rem's "explosive" declaration that she will kill Light if Light kills Misa "makes Misa's existence even more dangerous."