Sure Fire by Jack Higgins and Justin Richards
This was a classic action book. There was lots of fighting, lots of spy stuff, and lots of blowing things up. Although it was good, it wasn't original enough to make me want to read it again. There was also some swearing.
When Rich and Jade's mother dies, the are sent to live with their father John Chance, a bachelor they have never met. They quickly discover that something is not quite normal about Chance's lifestyle. When Chance is kidnapped Rich and Jade discover that their bachelor dad is actually a spy working for the government. Rich and Jade must decide who they can trust in their struggle to rescue their dad.