What is the main conflict in Stormbreaker by Anthony Horowitz?

In this novel, Alex's uncle dies in what he is told is a car accident. However, after doing some investigating on his own, Alex discovers his uncle was actually murdered. Convinced he never really knew his uncle, Alex continues to try to find out why someone would kill him. This leads to a meeting with Uncle Ian's employers who tell Alex his uncle was a spy for a special division of the MI6. Alex is blackmailed into finishing his uncle's case, a case that could lead to Alex's own murder. Stormbreaker is an exciting, suspenseful novel that jumpstarts the career of a highly unusual spy.