Why does Thor enlist Lukas' help in "Wildfire in Manhattan"? What does Lukas do?

Thor enlists Lukas to help him protect the god of Sol, Sunny from the Shadow and his minions. She has an innocence that is immediately evident, and when the wolves arrive, Lukas finds himself engaging Chaos. Just when all seems lost, Sunny offers to help. She simply puts up an umbrella and smiles.