What is the tone of “One of Us is Lying” by Karen McManus?

My literal favorite book! The one would be kind of mysterious and dark at points. Think of it as if someone is speaking behind the shadows, narrating (even though its 1st person, but just pretend to imagine it) and telling you the events that occur. It's also light in some way.

Explanation:

Exposition: Nate, Browyn, Cooper, Simon, and Addy are in detention for having phones in class. A minor car crash happens outside and the teacher heads out there. Simon takes a sip of water, and there, he dies. Addy goes to get an epipen, but doesn’t find it. Later, Simon dies, and the four are in suspicion of his murder.  

Rising Action: All of their secrets were to be posted the next day on Simons app but they couldn’t be since he is dead. This allows for more suspicion to fall onto the four. The police show them what Simon would have posted, and they all are mortified. All, except for Cooper as what was written is not what his secret was, he did not take steroids. They all are proclaimed outcasts and no one wants them around. Coopers secret later on gets out. Because they all had something against Simon, they were in even more suspicion. Especially Browyn how bad told Simon to die a year back. An entire stash of epipens are found at Nate’s home, leading to his arrest. The other three can’t believe it. Browyn says that Nate’s home is always home, anyone could have put the pens there.  

Climax: Addy goes to Simons friends house, she had been there for Addy when she was crying in the bathroom. Addy hides and Jake comes in. While Addy is recording everything, Jake asks Janae why she put the pens in Nate’s house and not Addys. When Janae says she doesn’t want to be a part of it, Jake tells her that he’ll plant all the evidence on her. Then, Addys phone rings and Jake chases after her. Right before he can throw a giant rock at her, killing her, Cooper is able to stop him. With the recording, Jake is sent to jail.

Falling Action: From Janae, they find out that Simon had planned his own death with her and Jakes help. She said that he wanted to get back at them for the things they did. He wanted to take his own life, and make the fours life a living hell.  

Resolution: Nate gets out of jail, but feels guilty that he wasn’t able to help the rest. Ash (Addys sister) gets a new home and invites Addy to live with her. Happily, she agrees. Browyn had a future at Harvard perfectly set, as they did not mind her and invited her to go there. Cooper continued with his baseball dream, and his secret being accepted. Nate stopped dealing drugs and tried to maintain a healthy relationship with his mother.  

the answer is allusion. give me brainliest