A possible concise summary is:
Two people, Mike and Miriam, are stranded on an island after a plane crash. They try to survive by looking for food, water, and shelter. They encounter cannibals and monsters in the forest and caves. They find a boat with a recording of a missing child and a locked chest. They decide to stay on the boat and declare themselves husband and wife.
Here are the key facts extracted from the text:
1. A nuclear fusion reaction was sustained at over 100 million°C for 30 seconds.
2. The reaction achieved a net energy gain.
3. The temperature achieved is nearly seven times hotter than the core of the Sun.
4. The core of the Sun has a temperature of about 15 million degrees Kelvin.
Please note that these facts are based on the information provided in the text and should be verified for accuracy.