The Magic Yellow Stone book one --Tom with the Carthaginian army

Chapter one - A Strange Stone was found by Tom.

Once there was an English boy named Tom, 16 years old. He was thin and tall, but with strong muscles.
His hair was brown and cut short. His eyes were blue. His face showed a dreamy expression, although he was a bright and clever boy.
He had a sister named Helen. She was 15 years old. Her hair was blond and long and her eyes were blue like her brother's. She was nearly as tall as her brother. She was nice but not beautiful.
Kind-hearted, she loved her strange brother.
They went to visit Rome in Italy with their parents on a guided tour.
They flew to Italy on a plane together with the other group members.
Arriving in Rome, they got on a tourist Italian bus. After everyone introduced himself to the English-speaking guide, the guide introduced himself as Alberto, a strong man in his forties.
The bus took them on a tour of Rome.
At midday, they stopped for a meal in an Italian restaurant.
Tom was one of the first tourists to finish his meal, so he went outside, found a big tree, and sat to rest under it.
Wanting to rest, he looked around and saw a yellow stone covered with dust.
He took it and took out a clean cloth from his pocket and cleaned the stone. Then something strange happened.
He felt pushed back by a strong wind.
When the wind stopped blowing, he found himself on a mountain's path.