Ryuk:”Light, why do you come to such an isolated place?”
Light:”Once a person touches the Death Note, he/she will be able to see you, right? What a headache. If Sayu sees you, she will get a heart attack & frighten to death.”
Light is doing some experiment for future use while L is still cracking his head thinking about KIRA case.
Light & Ryuk go to buy some material to hide his Death Note as Light believes that L has begun to suspect his relationship with the police. Therefore, there's a need to hide it & make it impossible for the police to search it out.
Ryuk:”Why do you deliberately make L suspects the police? For L to suspect that KIRA is related to them, doesn't it make it more unfavourable to you?”
Light:”The answer to your question… is to trace L & get rid of him!”
Light:”It's impossible to find L just by hiding the Death Note. In the human world, very few people actually trust one another. Furthermore, will you trust someone who has never shown his face & you don't even know his real name?”
Light:”L will definitely investigate on the people connected to this case secretly & he will know my relationship with the police. By then, when the police knows about what he has done, they will not tolerate him anymore. They will then track down L & I… will destroy him…”
[Police Headquarter]
Many police tender their resignation. They fear of death as they know that KIRA has the power to kill just by knowing the looks & name. They think that KIRA will attempt to kill whoever wants to arrest him.
[Light's room]
Light has hidden his Death Note in the drawer.
Ryuk:”That's not Death Note, it's only a normal diary!”
Light:”Most people will be contented just to see a diary. The key is also put at a very obvious location but in fact the real key to the drawer is the lead of a ballpoint pen. Even it is dropped beside the desk, nobody will suspect its use.”
Light:”There's a little hole underneath the drawer. Noone will notice it if you don't look carefully. Insert the lead of the ballpoint pen to the hole…”
Ryuk:”In order to make a 2 layer drawer, that's why you went to HOMECENTRE to select the material. With the fake diary, the Death Note will not be discovered.” 
