You love your work as a researcher on a small submarine. Your dream has come true now that you are mapping out the most unexplored places on earth, deep-sea caves. You work with a team of individuals who you now call friends. The work is not easy, requiring significant physical training and apart from your knowledge of marine biology, you have also had to learn quite a bit about submarine technology.

You realize that your undersea adventures are not without risk, but you have never had any real concerns.

Today is the last day of your mission, which is being conducted just off the coast. While you and your colleagues are setting up the camera to fi lm the reefs in the front compartment, you suddenly hear a loud bang. A collision? A torpedo? The submarine shakes on all sides, the lights and computers shut down and then you hear a frightening scraping sound. It is as if you have gotten stuck somewhere and the ensuing scraping along the rocks and cliffs cannot be good for the sub. You help your friends back onto their feet. You see the emergency lights that indicate that the generator responsible for charging the batteries is broken. The sub is damaged and may even have sprung a leak. There is just enough power in the main battery to generate oxygen for an hour. There is too little power to operate the sub the usual way (electrically), so you will have to perform all operations manually. Everything from navigating; to locating and restarting the engine; to rising to the surface. Luckily, you find the old fashioned emergency manual! Your lives are on the line…