Vengeance of the Tech-Powered Crown Prince

The third prince and Selene took the credit for the work Alexander had done at court and then had him killed for it. Alexander had come from the modern world into Great Zhou and woken up in the body of its crown prince, and he had been using what he knew of later centuries to pull the country out of the state it was in. He woke again on the night before the coup. The piece of jade he carried turned out to be able to call up modern technology, which he had not known about the first time round. He took the direct route after that, going at his enemies with force and leaving them no room. A crisis on the barbarian frontier came up in the middle of it and he dealt with that without much difficulty. Then something went wrong back at the palace and he returned for it.