This trophy is self-explanatory - one must make it through Story Mode. To make this easier, put the game settings on Easy and 1 Round. Going through Story Mode it doesn't seem to matter which opponents you choose to face. At the end you will fight Ragnarok - a large mech whose weak spots are denoted by large gem-like circles spread throughout. It's a cheap boss so just whittle away at each gem until it dissipates and be sure to use the A button to rush out of harm's way when he readies his large laser attack (will be obvious).