"Motor Matt's Submarine; or, The Strange Cruise of the Grampus" by the author Matthews is a thrilling adventure novel written in the early 20th century. The story revolves around the protagonist, Motor Matt, a skilled young motor enthusiast known for his daring exploits with various vehicles, including submarines. Joined by his friends, Matt finds himself embroiled in a dangerous adventure on the submarine Grampus as they pursue a mysterious antagonist named Captain Sixty, who seems to have ulterior motives connected to their mission. At the start of the tale, we meet Motor Matt and his companions as they await word from their friend Captain Nemo, Jr., who is recovering from illness. The plot soon kicks into gear when a sudden turn of events leads Matt to receive a telegram meant for Captain Sixty, which thrusts the boys into a tangled web of intrigue and danger. As the narrative unfolds, Matt and his friends are lured onto a voyage aboard the Santa Maria, where sinister actions by Captain Sixty put them in jeopardy. In a shocking twist, Matt is thrown overboard by Sixty, only to be rescued by the Grampus, which raises the stakes further as they seek to uncover the truth behind the treacherous plot that envelops their adventure. (This is an automatically generated summary.)