Jennifer was a young law student and super-heroine.
Jennifer was a member of the all female super-heroine team A-Force.
With the intention of conquering Earth Malekith used the power of the Casket of Ancient Winters to envelop Earth in a state of Eternal Winter, he would then use his army of Frost Giants and Dark Elves to finish the job.
Thor and Angela came after him from Asgard to stop him, Jennifer and her A-Force teammates were recruited by Thor to help defeat Malekith.
The Avengers Academy heroes also joined the battle. Jennifer and her A-Force teammates became members the Academy during the conflict.