nachdem. The clause that came first.

nachdem means "after." Like weil, it sends the verb to the end of its clause. But it does something weil never does: it forces that clause one step back in time.

After, but which clause happened first?

nachdem links two events. The event inside the nachdem clause is the one that finished first. The other clause describes what happened next, once the first event was already over.

The verb goes to the end

Like weil, dass, and wenn, nachdem sends the conjugated verb to the very end of its own clause. With Plusquamperfekt or Perfekt, that "verb" is really two pieces, the auxiliary and the past participle, and both move to the end together.

nachdem clause (verb cluster at the end)	Main clause
Nachdem ich diePrüfung geschrieben hatte,	habe ich gefeiert.
Nachdem wir gegessen hatten,	haben wir einenFilm gesehen.
Nachdem dasKonzert geendet hatte,	sind dieLeute nach Hause gegangen.

The comma is required, exactly as with weil. If the nachdem clause comes first, the main clause inverts: verb, then subject.

One step back: the tense nachdem demands

This is the part that decides whether a sentence with nachdem sounds right, no matter how clean the word order is. The nachdem clause cannot use the same tense as the other clause. It always sits one step further back on the timeline.

Other clause	nachdem clause
Perfekt or Präteritum (simple past)	Plusquamperfekt
Präsens or Futur (talking about the future)	Perfekt

If the rest of the story is in the past, nachdem needs Plusquamperfekt → hatte or war plus the past participle. For everything about building that form and choosing between hatte and war, see Plusquamperfekt. The past before the past.

Two events in the past

• Nachdem sie dasAuto verkauft hatte, hat sie einFahrrad gekauft. (After she had sold the car, she bought a bike.)
• Nachdem wir gegessen hatten, haben wir einenFilm gesehen. (After we had eaten, we watched a movie.)
• Nachdem dasKonzert geendet hatte, sind dieLeute nach Hause gegangen. (After the concert had ended, people went home.)

All three follow the same shape. The earlier event sits in Plusquamperfekt, finished and closed off, before the later event in Perfekt even begins.

Two events that have not happened yet

nachdem is not only for stories. The same one-step-back logic applies to plans and predictions. If the main clause talks about the future, using Präsens with future meaning or Futur, the nachdem clause drops back to Perfekt, even though nothing has happened yet.

• Nachdem ich diePrüfung geschrieben habe, fahre ich nach Hause. (After I've written the exam, I'm going home.)
• Nachdem wir angekommen sind, kaufen wir dieTickets. (After we've arrived, we'll buy the tickets.)

In English, both clauses can sit in the present ("after I write the exam, I'm going home"). German cannot do this. The earlier event still needs its own, earlier-looking tense, even when the whole sentence is about the future.

nachdem vs. nach

nachdem looks like nach with dem stuck on the end, and historically that is exactly where it comes from. Today the two work completely differently. nach is a preposition. It takes a Dativ noun phrase, nothing more. nachdem is a conjunction. It takes a whole clause, with its own subject and verb.

	Followed by	Example
nach	a Dativ noun phrase	NachdemKurs gehe ich nach Hause.
nachdem	a full clause (subject and verb)	Nachdem ich denKurs beendet hatte, bin ich nach Hause gegangen.

Same idea, after, but one points to a thing and the other points to an event with its own grammar.

For the full Plusquamperfekt structure and forms, see Plusquamperfekt. The past before the past. The verb-last rule from the beginning: weil. The verb goes last.