I have a wedding that was okay on Monday and then Tuesday morning, the images went "missing or offline". Tuesday adobe chat tried to fine the images and now they are all still offline/missing, however instead of me actually being able to see the photo, all I see is a grey space where the photos should be. Note: I use Lightroom 4
If you moved the photos outside of Lightroom, you can simply use your operating system to move them back.
Otherwise, the instructions for fixing this are here: Adobe Lightroom - Find moved or missing files and folders
Tell us exactly what you have done starting with importing the files