What is a default object?

What is a clean solution to display a ‘default’ message to the user, when something they try to access isn’t there (anymore)? We could let the our repository throw an exception, catch it somewhere, and then let our controller handle it. Maybe we could return null, and pass that all the way up and add a fall back message for the content in the view somewhere? Why not try a better solution and work with a default object.