This is the fourth post in english... i think, and in it I shall try to explain my point of view regarding the adventures.
There are may definitions for adventure but I like this one: it is a part of the whole story that you and your friends are making together and it is changing from the first idea to the end of the session.
And i like this definition because it is the real thing that happens when you are playing a game, because you can prepare so many encounters, traps, doungeons, Non Player Characters (NPCs)... but if your players happen to find an option you had not come with, most of all that you have had ready, go to hell and you must to begin improbisating. And that happens nine in every ten sessions.
An adventure must have three clearly differents parts. The first is always to be the introduction to the story, depending on the setting you can use different hooks, i.e. the barman in cyberpunk or medieval-fantastic RPG, The boss of the Player Characters (PCs) like the Inquisitor in Dark Heresy... somebody or something that makes the inclusion of the PC into the plot of the adventure easy. The next part is de climax, the core of the plot, here you need to create some problems for the PCs. For instance, traps and riddles, plots inside plots, encounters with dangerous or important NPCs... and information that the PCs can get if they do things correctly. In time terms, this is the latest part of the session, usually. The last part is the outcome, the ending. Here you usually face one of two options: your PC have worked well and got to the goal (the stolen files, the heresy, the treasure) or not (they are dead, without tracks, lost inside the dungeon).
You must to Konw that usually the PCs always do something you did not expect. In that moment you may have to improvise trying to drive the PCs back to the main line of the plot. On the other hand, you can always go on with the new way you and your players are creating an explore it with them.
Well, that is all.
See you soon (I hope).
If you find writing or grammar errors, please write to correct it. Thank you.
EDITED. Correct many mistakes. Thanks Esculapio 0 for all.