How does Dee come to think that there is a lost Modigliani?

What is the cause of the problems between Sarah and Julian?

Why is Julian interested in the lost Modigliani?

How does Lipsey find the old man who told Dee about the Modigliani?

What was the art swindle of the century that Peter Usher and his friend Mitch concocted?

What was the reason for the forgeries?

How was the forgery swindle resolved?