Campaign Story Help

Hey everyone. I have a basic idea for a storyline, but need the plot points to fill it in.  It is a pirate themed campaign. The game starts with the players waking up in a dark room tied together. Pirates have taken them prisoners. When the players escape they are faced with the crew in a battle. When they defeat the crew they are faced with the captain. If they can't handle the captain, a cannonball will hit the ship (regardless of win or loss in fight). Another pirate comes aboard and rescues the players. The pirate goes around looking for evil pirates, he takes their treasure and rescues their prisoners. The pirate feels that he can't do wrong and that all he does is just. The crew and players will find him to be a saint until the players find out how crazy and over the top his actions are when the players aren't around.  Now the help I need is, What happened in between?

Eh... waking up as prisoners without and gear is cliche and speaking for myself, I would be very bored with the scene. It's almost as bad as starting in a tavern. I suggest having three ships: the player's ship, the evil pirate ship, and the crazy pirate ship. Start the encounter with the pc's ship taking cannon fire from the evil pirate. Blast their rudder and main mast and start boarding. Then have the crazy guy come in and blast the evil pirates with a crap ton of cannons.

cliche is ok, we are all new and getting basic stuff is best

I kinda like the tied up in a room together thing. It makes introductions easy and puts everyone on the same page for motivation. Get the hell out of here! Now as far as future plot ideas... do you have an antagonist in mind for Cpt. Crazy? that one pirate he's always been hunting, the great white whale so to speak, the barbossa to his sparrow? I suggest having the party help hunt down a pirate crew and Cpt Crazy does something stupidly heroic, that also shows great disregard for his, and other's well being. It ofcourse will all turn out ok, because he's the bad ass hero in his own mind and events like this re-enforce that he is doing the right thing all the time.

Or the "You all wake up in the same cell.  Last you remember was someone buying rounds at the Tavern"

A Gm for a tabletop game did something that worked well for our group: We started in a room. We were fully awake. On the floor lay a man who had been shot (in your game he could have a dagger in the back). no explanations as to why we were there, or what had happened even though something had obvioulsy happened. I checked my clip, and found two bullets missing (One player could have an empty scabbard for the dagger), and immediately we started concocting crazy stories as to why we had killed him (since our characters by virtue of their backgrounds had A LOT to hide). Slowly we discovered more and more about what was going on.  A very cliche way of starting given a twist that suddenly made it new and strange.

If we are working the pirate story telling mechanics, here are a few I can come up with: Forced to walk the plank. Darkness only pierced by swining lanterns (great opportunity to use dynamic lighting if you have access to dev roll20). The maiden in distress / kidnapped noblemans daughter. Swinging in ropes. Inept henchmen Since you have the "good guy turning out bad", it is a good idea to drop small clues along the way, in the form of micro plots that plays with the "things are not what they seem". Monster turning out to be good guy. Governors daughter is a bounty hunter or assassin who let herself become captured in order to get close to her mark. The captain of the royal navy is a cruel and wicked man despite his reputation as a saviour. In story telling it is called literary symmetry and it works really well, even though the players wont recognise what is going on, it is preparing their minds for the possibility of their saviour being insane (plus it is fun to do the "I am not who you think I am" bit)

Thanks Soren, I am so going to use the governor's daughter story. It will fit perfect into the storyline.