Earth is under attack by the powerful force known as Onslaught. Humankind is in danger and the only ones who can save it are the Super Heroes of the Marvel Universe and the Capcom Universe. This is the story for all of the characters in Marvel vs. Capcom as none of them have individual storylines. Everyone is simply out to save the world by defeating Onslaught.

Marvel vs. Capcom features a number of modes of play: Arcade, Versus, Survival, Training, and Cross Fever. The game is all about tag-team fighting, each player selects a pair of characters before going into battle. Survival mode allows players to choose a team and fight one team after another while regaining only partial health until they lose. Training mode is where, as the name of this mode indicates, players practice moves and combinations.

Versus mode pits two players against each other. Both players select two characters and battle it out in a single match. Cross Fever allows up to four players to take part in a battle. As in the rest of the game, only two characters battle at a time. The other two wait offscreen until their partner tags them into the melee. There are instances where both characters of the same team can be on the screen at the same time but for only a short period of time. This occurs when the player currently fighting uses a special tag out combination. As the other player comes into fight the two characters attack the enemy together before one of them exits the screen.

Arcade mode is always against the computer. If a second player joins in the game defaults to Versus mode until the match ends. After the match ends one player can continue with the Arcade mode or the two players can play a regular match again. During Arcade mode one player selects their team and then goes to battle. Defeat the randomly chosen computer teams and then overcome the power of Onslaught in order to be victorious. After each loss players have the opportunity to continue and to select a new team of characters.

Who will take part in the battles mentioned above? In total there are 15 playable characters. From the Capcom Universe we have: Ryu, Captain Commando, Chun-Li, Zangief, Jin, Morrigan, Mega Man, and Strider Hiryu. Included from the Marvel Universe are: Captain America, Spider-Man, Hulk, Wolverine, Gambit, War Machine, and Venom. Other characters featured in Marvel vs. Capcom are called guest characters. Before going into battle a roulette wheel determines who each teams guest will be. Guest characters can be used a predetermined number of times during a battle. When called upon they enter the screen and make an attack on the enemy.