Draw three exciting cover for a time travel trilogy!

I need three book covers. I wrote a trilogy, published 2004-2008, subject: time-travel, now I want to republish the three novels as selfpublisher. The three covers shall show the same figures in different settings - medieval, roman times and near future. In the first novel, "1227 - Lost in the Middle Ages", Nelson, an approximately 14-year-old, rather unassuming boy and his friends Luke and Judith disguised as monks could be seen in front of a huge castle. For their journey, all three have their hair shaved so that they wear a tonsure. A knights' tournament with the three as spectators would be conceivable. As Judith throughout history as a beautiful maiden dressed with flowing blond hair, would also be an option. Content: The three friends want to free Levent, a former student of her boarding school, which has been lost in the Middle Ages (in the year 1227), there sits in jail and faces death. In the second part, "168 - Lost in the Roman period," Nelson, Luke and Judith travel to the Roman times to find a brother and sister, who apparently traveled to the year 168 in a time machine from the future. The boy who is called Oceanus has been enslaved as a gladiator. When the three friends arrive they wear a Roman tunic. The cover could show a gladiator fighting, for example with the three friends as spectators. Threatened is their mission by the Norton twins that are traveled after them in the past and in the third part again wreak havoc. In third part, finally, "2033 - Lost in the future", it is about the first manned Mars expedition in the history of mankind. Astronauts are the parents of the missing siblings in the 2nd part. They are attacked by the so-called space pirates, in reality the Norton Twins, who want to sabotage the mission. In its bailout the friends, this time they are four (with Levent), land in Cologne the year 2033, a futuristic city where skyscrapers tower above the cathedral itself. Perhaps one of the skycraper-fronts could capture the Mars journey more or less as canvas spectacle, as in New York anywhere giant screens hanging on the skyscrapers ...

The three book covers, published in 2004, 2006 and 2008 (see below) were too different. I would like that people recognize the characters. One example: the seven Harry Potter Covers. But my characters travel in time over a period of one year, therefore they do not have to grow old on the covers. I can pay up to 500 Euros for the three covers. I know that this is a bad price but as a freelance writer this is my budget...

Every design category has flexible pricing for all budgets. Book cover starts at $299.