A person is locked up in a mental institution because he claims that he's been having clairvoyant visions from ages long time ago. At some point, it becomes evident that he actually tells the truth and that he indeed can see the past, just as if he was there.
It is a gold mine for the historians, so the police and others so the authorities immediately issue an order of release. However, due to some confusion at the mental institution, it's unclear who he is. After eliminating all possible candidates, the correct selection process produces two individuals - Adam and Benny. Precisely one of them is guaranteed to be the medium with superpowers, while the other is a fraudulent liar. The problem is that there's no way to determine who's who.
Both of them claim to be the true psychic and both state that they're immensely upset with the unfair incarceration in the mental institution. As a result, both refuse to provide any new story from the past to verify the ability.
Finally, both agree to tell one story each. The subject is a feast at a house of a Viking family and based on that, we need to determine who's the true asset and who's a darn cheat.
We started with a main course consisting of beef and a side salad of carrots and cabbage. The beverage was served first afterwards, together with mashed apples cooked in cow milk and flour. There was no singing and the conversation was in English.
First, we had some beer, not very strong, and then water. We were served pork dipped in fat and burned almost to well-done over an open fire. On the plate, we also got eggs and some kind of mix of tomatoes and potatoes. For desert, we had a cake with a lot of berries. It was noisy from the music and singing.
After being presented with the above information, a person stands up and states: "I know who's got the super powers!"
Who is it and why?
The language remark is a honeypot - it's actually not the issue at all. Vikings did visit England and it's possible that they spoke the language. Also, there's been Vikings living on the British islands and I never said where the feast is taking place. Also, it's possible that the guests at the feast were visitors from England.