After the discoveries at the conclusion of 'Impact', it is only a matter of time before the Narlavs attack.... As the small group of defenders prepare for the battle, they have to deal with extreme weather, desperate survivors, and still search for lost friends and family members. Richard and Karen have to bring disparate forces together, uniting them to maximise the hope that they still have... to survive... and more than that, to win Cavalry is the 4th volume in the Galactic Citadel series. Thorby Rudbek's books are adventures with a little romance. Suitable for both young adults and older readers, his works are optimistic and exciting, without extreme language or explicit subplots.