Complex sentence: The Doctor becomes suspicious of Monarch and soon learns that the Urbankan does not plan on peaceful co-existence; instead, he has developed a toxin to wipe out humanity, which will be unleashed before the Urbankans disembark.
Split into simpler sentences: The Doctor becomes suspicious of Monarch and soon learns that the Urbankan does not plan on peaceful co-existence. Instead, he has developed a toxin to wipe out humanity, which will be unleashed before the Urbankans disembark.