Can't get to Osgiliath in story mode?

[Muñero]

So after completing Helm's Deep, I closed the game to continue the next day.
When I started up again Legolas, Gimli, Gandalf and Aragorn are in Middle Earth a long with Frodo and Sam who are also in Middle Earth but in a different place.
I've watched some walkthroughs online and it appears that you're supposed to take a path to get to Osgiliath, but when I play that path doesn't exist and Frodo and Sam spawn right next to the entrance to the Dead Marshes level.

I've tried everything I can think of to get to Osgiliath, but all the written guides and video guides don't show anything special.

Any help would be wildly appreciated as me and my son are playing co-op and want to beat this game together.

Thanks

[Mastertesla]

In case it helps: I just finished Helm's Deep and all I had to do to start Osgiliath was switching to Sam n Frodo and following the slightly transparent blue lego stones (which usually lead to the next level)

[Muñero]

Originally posted by Mastertesla:

In case it helps: I just finished Helm's Deep and all I had to do to start Osgiliath was switching to Sam n Frodo and following the slightly transparent blue lego stones (which usually lead to the next level)

That's what I've seen in playthroughs on YouTube but for some reason when I switch to Frodo and Sam the blue trail leads to the Dead Marshes.

Makes me wonder if it's a bug or something

[Mastertesla]

Maybe. Have you tried beating Dead Marshes again? Maybe it just didn't register you beating this level for some reason.