Plugin Mouse - Not working?

I'm trying to detect when the mouse.Button1Down is fired with my plugin, but everytime I attempt to, it doesn't work. I've read over the wiki several times and I don't understand what I'm doing wrong.

My Code:

local mouse = plugin:GetMouse()

mouse.Button1Down:connect(function()
    print("Fired")
end)

Nothing happens in the output. If someone is familiar with plugins, and knows the nature of this frustrating bug, your help would be appreciated! :).

Thanks, ~ObscureEntity