1 Prof. Jones: {hoisting a sword} I can't believe they actually left this lying around where we could reach it. Those Nazis are pretty stupid, Junior.
2 Monty: I don't know, dad. They got clean away with the Egyptian Book of the Dead and the Mayan Codex.
3 Monty: They'll be halfway to Berlin by now.
3 Prof. Jones: My point exactly...
3 Prof. Jones: Leaving Rio de Janeiro the week before Carnival!

I struggled mightily to come up with a decent gag for this one. My first attempt:

But this was more plot advancement than funny, and we can't have that! So no Excalibur.

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2012-07-12 Rerun commentary: Ah, Professor Jones demonstrates his hedonistic streak.

Also, the timing of Rio's Carnival means this strip must take place in late February. Now if only we could narrow down the year...