In this the 9th book of the series, Neptune is rather depressed on his journey home from Australia thinking that it is the end of his partnership with Shark. Imagine his delight then when he learns Shark has been trying to contact him. He rings him immediately and is relieved when Shark tells him he is returning to England as his mother and siblings have decided to emigrate so she could be reunited with her sons and so Shark doesn't feel he has to sacrifice his life and business to look after them.

With renewed purpose, Neptune tackles a missing person case with Rachel as his able assistant and uncovers a murder instead. While still awaiting Shark's return, Neptune takes Rachel out to lunch and comes across a for sale sign on a decrepit building in Baker Street. He is taken with it immediately. It's Baker Street after all and how could he, Sherlock Holmes fan that he is pass up an opportunity like this. He wants to buy it and turn it into their new office. Rachel talks him into including Shark in the deal so that they could be join owners. Neptune's happy to do whatever she asks as long as he gets the building. It's a dream come true for him.

In The Case of the Panicking Princess, Princess Helena of Slovenka is being blackmailed and needs to retrieve a scandalous letter before her engagement party to Lord Cumberland. Once again Neptune is left to tackle most of this case on his own with some help from Rachel because Shark is sick. Neptune's not much better suffering from strange episodes of morning sickness.The letter's trail leads them on a fair chase culminating in some unlikely culprits.

In The Case of the Baby Snatchers, the boys become persona non grata at Scotland Yard when Chief Commissioner Chadworth suffers a heart attack and is replaced by stiff necked, unfriendly ex-military man, Chief Commissioner Talbot. Initially willing to work with the police, they decide to hell with them and go it alone. This is one case where they don't plan on sharing the credit with the police, especially when the case takes on international proportions. They meet colleagues from New York and join forces to stop an organized baby stealing ring covering two continents. Are they victorious?

Of course – they're Neptune King and Shark Johnson after all.