[4e] DM writers block

[zoobob9]

Ok, so we're contiuing a campaign and all of our PC's are level 2. The next meet is friday, and now im gonna be the DM. So instead of doing random adventures, i want a plot, and here is what i have so far:

In a continent thet i made up, there is a small town in an unaligned country whose name is irrelevant. there are five people in the party. Two (good elf beastmaster ranger, unailigned minotaur thaneborn barbarian) know each other form a barbarian tribe and are living out of town. they come in for a drink at a tavern. Another (unailigned dragonborn/vampire fighter) has come rom thearmy as a body gaurd for the mayor. two more (evil razorclaw shifter paladin and TBA, probably hybrid wizard/cleric) don't know each other, but are at the church in town, healing people. A gang member steals the mayor's wallet, they all meet up and kill the gang, mayor sends them on trip to other town to deliver a parcel. they go, do stuff there, go back to first town, everythings destroyed. they go to a banditr camp cause they think it was them, it was actually two dragon wyrmlings. they go, try to kill wyrmlings, the wyrmlngs escape. PCs find out that they are from rival nation, join in army, go to war. By this time they are like 3rd level, if that. they get capturd, break out, one of them dies. By the way, the rival nation is a desert. They find an archmage(who is almost exactly like Vaarsuvius!), he casts raise deadon he dead one and the PCs cant pay, so he casts mark of justice on all of them. If the PCs dont get him an artifact(tba which artifact) within like, 10 days, or have remove affliction about to be cast on them without V within 20 feet, they get teleported back to V's tower into prison cells, where they are killed or something. so they go into a dungeon, gain like 3 levels, kill a lich(who later turns one of the dragons above into a dracolich for an epic final battle), give the artifact to the dude and leave.

I have no idea what to do next. Please help.

P.S. im sorry for any typos, im a "look at the keyboard" typer.

P.P.S.: i have accidentaly put that they kill a lich and dracolich thing is immideate, it won't be until they're like, 29 or something. the lich alone will be by himself and only 2000 xp, which is hard for a level 5 party, but not too hard. Ill probably only give him like, 3/4 of his hitpoints too and lower his defenses. Also, the artifact is the head of Vyrellis. The Government of this country may beg to kill them because they are from their country, i don't know, so take that into account.

P.P.P.S.: the TBA character is a hybrid claric/shaman, and theelf ranger could be a Githzerai monk.

[Mando Knight]

Level 6 isn't "kill a lich" material, much less "kill a dracolich" material. Wyrmlings also aren't dracolich material.

If you're going to run a campaign with undead, grab Open Grave. For ones with dragons, get the appropriate Draconomicon.

Also, don't plan out defeats and victories that far ahead. It's rather bad form, especially since it'll look like the railroading it is if the players don't perform like you think they should. Plan out only the next session in full detail, with ideas for progressing the plot hooks for each successive session depending on the outcome your players achieve. That said, knowing the basic layouts of all the dungeons involved beforehand is useful.

Now: for an actual plot...
1.) Why couldn't this archmage do it all himself? If a party of level 3-6 characters could stumble through it, then a Paragon/Epic character should be able to just nuke his way through easily.
2.) What's the story behind that artifact? What does it do?

[Saintjebus]

Rather than trying to write out a story for your players to fulfill(which leads directly to railroading), give them a problem. Any problem. Don't think of a solution. That's the player's job. If they ignore the problem, progress it. They don't want to kill the goblins threatening the town? Then next time they try to go to the town, all of the people are dead, and they have to fight the goblins anyway.