Plagiarism is when you copy someone else's work (usually word by word) and you do not acknowledge that you where not the person who wrote it, also, you do not cite where you received that info from. That is why we have copyright laws, where the author can choose whether to establish a penalty if copied.
Hola amiga qué haces en el parque
I don't know which novel you're asking about. What book is it?
To creat an ominous tone that foreshadows Caesar's fate