"The Boy Allies Under the Sea; Or, The Vanishing Submarines" by Clair W. Hayes is an adventurous novel written in the early 20th century during World War I. The story follows two young protagonists, Frank Chadwick and Jack Templeton, as they delve into the mysterious disappearance of German submarines that have been wreaking havoc on British waters. The boys, both with previous experiences in naval adventures and espionage, are eager to partake in active service once again and uncover the truth behind the vanishing submarines. The opening of this novel sets the stage for an exciting tale, beginning with the two boys discussing the pressing issue of German submarines and the British response to them. Their conversation is interrupted by Lord Hastings, a British naval commander, who reveals that many submarines have inexplicably vanished. As the chapter progresses, the boys learn they will soon embark on another mission, heightening their anticipation for adventure. The dynamics of their friendship, the thrill of the unknown, and the backdrop of wartime tension promise a fast-paced and thrilling narrative as they undertake their dangerous exploits. (This is an automatically generated summary.)