"Secrets and Lies" is a song in Death Note: The Musical.
The case progresses and tensions rise. L works on tracking down Kira, wondering how he does it. In the first dialogue interlude, L asks Soichiro Yagami to look into how the victims were reported in the media, and if their names and faces were all exposed. Soichiro agrees and the Task Force gets to work. Soichiro sings about his disagreement with L's methods, saying they're no different from Kira's.
In the second dialogue interlude, Light Yagami is still trying to track down L, and he's guessed his father's password to look at the investigation reports. Ryuk offers Light the Shinigami Eyes in trade for half his remaining life. Light sings about the choice but declines it, going on about how he'll get L himself.
In the third dialogue interlude, the Task Force learns that 23 new criminals have died of heart attacks, one every hour. L realizes it's in response to his suspicion that Kira is a student, and suspicions turn toward the police and their families. Light's done this intentionally to increase infighting, and to get the police to look into L for him so he won't need the Shinigami eyes.
Immediately after the song ends, the arrival of FBI agents in Japan is announced on the news.
The song was originally written in English, but an English-language version has not been released. The original English title of the song is "Secrets and Lies".