It sounds like you don't need a run-down of the events of the battle but an explanation of its significance.... it was very dramatic and the battle itself is a 'classic' but its real importance is for other reasons...
The attack on Pearl Harbour, from a Japanese perspective, was a major gamble: America was a far more powerful country, but her naval forces in the Pacific were not large. The Japanese had invaded China, for reasons very important to the Japanese military, which had gradually taken over the once-democratic Japanese government. They were determined to build an empire like the 'great' European powers, to be respected among nations. China was to be that Empire. America was disgusted by the invasion and the behaviour of the Japanese Army- they imposed economic sanctions on Japan which hit Japan hard.
Japan by late 1941 had the choice- abandon their war in China, which was unthinkable- or cripple America, sweep up the European colonies in souther Asia to secure their oil and rubber and other materials for the war in China, and then negotiate peace with the 'crippled' America. This was the Pearl Harbour plan.
As history records, the US lost a significant part of its fleet at Pearl Harbour but its aircraft carriers survived. Unknown at the time, these were to be the only important ships in the type of fighting that was to come. Into 1942, the Japanese were everywhere strong: they forced the US out of the Philippines, the British out of Singapore, and threatened Australia. This big new empire needed sea power- and it stretched Japan's military resources over a wide area. The American navy was weak, but still in the fight. Japan was also not in any position to wage a long war- as was recognised in the Pearl Harbour plan.
The Battle of the Coral Sea in early 1942 was fairly even- Japan's expansion was stalled, but no side won a decisive victory. At Midway, the Japanese planned to win that victory by trapping the Americans and sinking her last major ships.
As another answer person has said, broken codes revealed the Japanese plan to the Americans, and they turned the tables on Japan. Assisted by the 'fortunes of war' and a lot of luck, plus great skill by US pilots when it counted, the Japanese lost all four aircraft carriers and, crucially, all the aeroplanes on them (which of course had nowhere to land, or sank with the ships), and even more crucially, their aircraft crews. Flying naval aircraft at the time was very difficult and Japan lost hundreds of trained air crews.
Japan was suddenly much weakened. Over time, American industrial might kicked in. The long war the Japanese planners, notably Admiral Yamamoto, feared was a reality. She no longer had the resources to inflict a decisive blow on America. Her defeat was a matter of time.
The Japanese lost three of their aircraft carriers in five minutes at Midway- now you know what was hinging on it, you can see why it's a dramatic battle!