Video clip on the map (adventure dialog).

The winner is right. Duncan, have you never done any programming? Here, as well as there, there should be no improvisation; everything is done only through functions, and a list of them can be found in the manual (game folder/Editor Documentation/A2_Script_Functions.pdf).
And the text is indeed not created through a script. How to do it is shown in the example. The principle is roughly the same as with the description of the prophet's hut quest.