Love is like war

It all started with a letter... Amon, whom his parents named after the Egyptian sun god, found it in his mailbox. In the letter, someone signed "Shadow" promised to follow him until the right moment for revenge arrived. Amon was not afraid. He was sure that his “shadow” was harmless... Lada, who lives next door, also read the letter. And she decided that the message was addressed to her, and that it had ended up in Amon’s mailbox by mistake. Lada was scared. Because the one who wanted to take revenge on her was a very dangerous person... Soon Amon’s friend was killed, and Lada’s friend was attacked. Who did this? Whose shadow began to take revenge?