When Nami wakes up, she is shown to be in some kind of Lego/toy building and not knowing where she is. The theory is that since the Thousand Sunny is missing, it drifted off to Elbaf on its own(Sabotaged maybe?) when everyone was knocked out from drinking, and a giant took them mistaking them for toys.
I'm bad at explaining(sorry) so I'll just show the image: