First , I'm following the Percy Jackson Novels and The Avengers and Harry Potter Movies (cause I haven't read The Harry Potter Novels)

Okay , so the timeline here is VERY disoriented....

1) This starts AFTER Loki and the first Avengers Movie!

2) This starts DURING the First Percy Jackson Novel , which is The Lightning Thief!

3) This starts DURING the Second Harry Potter Movie , which is Harry Potter and The Secret Chambers