Learn French: Nous allons voir la scène et le décor dans une seconde. - We are going to see the stage and the set in a second.

You are right that dans usually means "in" or "inside" a physical place (like dans la maison). However, when you use dans with a time expression like une seconde, deux jours, or trois mois, it means that an action will happen "in" that amount of time from now.

Why is it allons voir instead of just using the future tense of "to see"?

Allons voir is the futur proche (near future), created by combining the present tense of aller (to go) with an infinitive verb (voir). It translates exactly to "are going to see." You could use the simple future tense (nous verrons - we will see), but the near future is extremely common in spoken French, especially for things happening almost immediately, like dans une seconde.

Does la scène mean "the scene" or "the stage"?

It can mean both! In theater and film contexts, la scène often refers to the physical "stage" where actors perform, but it can also mean a "scene" in a play, movie, or daily life. Because it is paired here with le décor (the set), translating it as "the stage" makes perfect sense.

Is le décor a false friend? It looks like "decor."