If I was doing Indy 5 it would be called "Indiana Jones and the Sword of Arthur" (referenced earlier in this thread as being an abandoned script for Indy 4) the title would be a bit misleading since this would be primarily a Mutt adventure with him on an expedition searching for Excalibur. Mutt teams up with a female historian who's expertise is Arthurian Legend, she's also his romantic interest in the film. The two of them though are tagged by Russian KGB agents who also have an interest in the sword and who want revenge for what the Jones family did to their agent in the last film. The second half of the film would feature Indy and Marion (if Karen Allen was up to doing another film) rescuing the two of them. The twist is that Indy discovers that Mutt was actually hired by a dummy Illuminati interest (yes a bit like Lara Croft I'll grant you that). Not really sure how to end it except that they actually find Arthur's sword and meet the Lady of the Lake. Mutt and his lady friend discover an ancient druid scroll written by Merlin that actually leads them to where the Sword is. This is roughly based on my own Indy/Excalibur story I wrote when I was about thirteen or fourteen. I just added in Mutt and Marion.