In the latest installment, the Widow Ashton and her companion Admiral Faucet (pronounces Fah-say, if you please) have returned to the homestead. The Widow to see her son Frederick, and the Admiral to woo the Widow and to launch his money making scheme of ostrich racing. But when the pair arrive, Faucet's ostrich Bertha has escaped into the woods around the estate. In fact, Penelope and the children come across the ostrich while on a nature hike in the woods, but no sooner do they see her than Bertha is off and running again.
Upon meeting the children, the Widow Ashton is quite taken with them, and Lady Constance who has never shown the children any affection to speak of, starts to fuss over them. In fact, the first night of the visit, Penelope and the children are invited to dine with the family and they are regailed with the tale of Master Ashton's untimely death in a medicinal tar pit. After dinner Frederick and the Admiral take the boys back to the study and hatch a plan to get Bertha back. Faucet wants to catch her and Frederick wants to hunt her. And they want to take the children due to their unique tracking abilities.
Penelope won't let the go without her and Cassiopeia, and since she is worried about Frederick's abissmal eyesight, she conspires with Faucet to have the expedition take place on the full moon when she knows full well that Frederick will be suffering from his "moon sickness".
What follows is an adventure that only Penelope could get into with the Incorrigibles. Honestly, not as much happens in this installment as I was expecting. There are of course the elements of the Swanburne education with the exploration of philosophers like Thomas Hobbes and Jean-Jacques Rousseau, synonyms, and prognostics. There are also dappled mysteries like the sandwiches in the cave, and the identity of "Judge Quinzy". But it seems that the biggest thing that is happening in The Unseen Guest is Penelope's own growth. Why, for example, is she not finding the comfort she used to in the pony books of her childhood, and why does she yearn for adventure instead of comfort?
Overall, fans of the series will eat this one up. I do hope, however, that the next adventure brings us closer to the reveal of not only the moon sickness, but of the identity of Quinzy as well!