An introduction to the Stealth project, including what will be covered in the tutorial episodes.
The tutorial videos are available here:
There's a support thread for upgrading the project to Unity 5.x here which is probably of interest no matter what version of Unity you want to upgrade it to:
Also, I made an extended version of this project, available here:
Disclaimer: This project is no longer officially supported. Most likely you'll get no support from me either, just use take it for what it is.