Complex sentence: The new heir to the Caswall estate, Edgar Caswall, appears to be making some sort of a mesmeric assault on a local girl and a local lady, Arabella March, seems to be running a game of her own, perhaps angling to become Mrs. Caswall.
Split into simpler sentences: The new heir to the Caswall estate, Edgar Caswall, appears to be making some sort of a mesmeric assault on a local girl. And, a local lady, Arabella March, seems to be running a game of her own, perhaps angling to become Mrs. Caswall.