Как правильно пишется in the hour или in hour

We are going to be at home in an hour.

Это зависит от нескольких факторов: 1) если вы уже употребляли hour ,то с the  2) если вы говорите об определенном часе ,тогда тоже с the 3) in an hour(когда упоминаем в первый раз) в данном предложении я бы употребила an,точно без  the!

Peter the great or pyotr alexeyevich romanov (russian: пётр i алексеевич pyotr i пётр i фото/ peter i photo image picalekse`yevich, пётр великий pyotr veli`kiy) (9 june 1672 – 8 february 1725 [30 may 1672–28 january 1725 o.s.]) ruled russia from 7 may (27 april o.s.) 1682 until his death, jointly ruling before 1696 with his weak and sickly half-brother, ivan v. peter carried out a policy of "westernization" and expansion that transformed the tsardom of russia into the russian empire, a major european power.  peter, the son of alexei mikhailovich of russia and his second wife, nataliya kyrillovna naryshkina, was born in moscow. alexei had previously married maria miloslavskaya, having five sons and eight daughters by her, although only two of the sons—feodor and ivan v—were alive when peter was born. alexei i died in 1676, to be succeeded by his oldest surviving son, who became fyodor iii.  fyodor iii's uneventful reign ended within six years; as fyodor did not leave any children, a dispute over the succession between the naryshkin and miloslavskyi families broke out. ivan was the next for the throne, but he was chronically ill and of infirm mind. consequently, the boyar duma (a council of russian nobles) chose the ten-year old peter to become tsar, his mother becoming regent. but one of alexei's daughters by his first marriage, sophia alekseyevna, led a rebellion of the streltsy (russia's elite military corps). in the subsequent conflict, many of peter's relatives and friends were murdered—peter even witnessed the butchery of one of his uncles by a mob. the memory of this violence may have caused trauma during peter's earlier years.