The episode starts out with SpongeBob knocking on Patrick's rock saying they're going to have a shindig. Patrick jokingly says his shins should not be involved!
SpongeBob tells him that's shindig buddy, we're going to the beach in honor of our best friendship. Patrick says "the beach? Just you and me?" SpongeBob says "Yes, A little sunscreen and you'll do fine."
The local bus pulls up. SpongeBob and Patrick get on the bus. SpongeBob tells the bus driver that they're going to the beach in honor to commemorate their friendship. SpongeBob knocks into one of the bus' passengers. He responds with "You're hurting me". SpongeBob tells Patrick that they should start a few verses of the best friend tune. As soon as SpongeBob and Patrick start playing, the bus driver kicks them both off to what they think is the middle of nowhere. SpongeBob and Patrick both cry because they think they are abandoned.
Eventually a volleyball hits them. It's a volleyball player saying "Little help bro". SpongeBob takes out a small plastic disc that you throw. Patrick runs after it destroying the life guard's tower in the process. The life guard tells them that was not cool "Your buffoonery has destroyed the life guard tower". He then suggest that they go play in the sand. Patrick thinks this is boring and tells SpongeBob he should think of ways they can play in the sand. SpongeBob says they can practice their cursive writing. Patrick says "Boring SpongeBob, boring!"
SpongeBob suggests that they make sand castles. Patrick calls this "unboring". Scene cuts to SpongeBob's built castle. A king statuette made out of sand is in the top window. SpongeBob says he'll make a queen to go by his side. Meanwhile Patrick has built a castle of his own. Unfortunately Patrick's built castle is on SpongeBob's territory line. SpongeBob decides to remove the integrity of their shared border. Patrick destroys SpongeBob's castle with a hammer. SpongeBob goes back to square one and builds another castle just as quickly including 2 sand gargoyles. SpongeBob decides to get Patrick to sign a treaty to bring peace to their land, and includes a quill. Rather than signing the treaty, Patrick throws an arrow at SpongeBob's newest castle. Patrick hires an architect, however this plan backfires. Now Patrick has built a giant castle with horses. SpongeBob uses an axe on some rope which sends a projectile to destroy the horses.
SpongeBob blows on a horn then 5 sand guys with weaponry break open Patrick's door. However, Patrick quickly designs a cannon with matching ball which chases after the 5 buys. Although the 5 guys make it into the castle, the cannon ball decides to float upwards. SpongeBob says the famous quote: "How do you like them apples?"
The cannon ball destroys the 5 guys.
Patrick laughs evilly in the background. Meanwhile SpongeBob enters what appears to be from the outside and inside a secret government type lab. He uses his thumbprint identification to enter. He's created a massive plan. He asks a sand general what he thinks and the general disintegrates. SpongeBob jumps into a military plane and destroys Patrick's castle, although through all the destruction, Patrick falls down and appears to be unconscious. SpongeBob asks his best buddy if he's OK, Patrick is now completely alive asks SpongeBob "The question is, will you be?"
Patrick soars on with a jet pack leaving SpongeBob about to fall into the ocean. However SpongeBob uses a parachute and arrives in another fighter jet plane and shoots 3 sand missiles at Patrick's jet pack which is now a giant robot. He says "Two can play at this game".
He launches more missles at SpongeBob. The missiles keep attacking SpongeBob until he decides to duck down and let a couple missiles hit the other missiles and create a nuclear explosion. Some fish notice the missiles coming, everyone decides to leave the beach except SpongeBob and Patrick.
Patrick destroys SpongeBob's castle but SpongeBob destroys Patrick's robot. Both are now on land with black eyes. Patrick questions SpongeBob if it was worth it. SpongeBob generally says no. The life guard from earlier reappears to tell SpongeBob and Patrick to clean this place up. Then SpongeBob and Patrick compete to see who's faster at cleaning up. The episode ends.