The Central Powers win the Great European War (WWI in OTL) and imposes their hegemony over Europe: Germany, Austria-Hungary and the Ottoman Empire are the «superpowers» of the world in the first half of the 20th century, but the emergence of a new superpower could ruin the party.
Point of Divergence
In our time line, the Central Powers of the World War I only were Germany, Austria-Hungary, the Ottoman Empire and Bulgaria, however, in this althist, the Central Powers are Germany, Austria-Hungary, the Ottoman Empire, Bulgaria with the belligerence of Denmark, the Netherlands, Belgium, Italy and China; the United States are neutral during the war. This equalizes the situation and gives the chance for the Central Powers get the victory of the war.
With the abandonment of war in Russia in 1917, Germany stabilizes the eastern front and creates the Regency of the Kingdom of Poland, a puppet state.
On the western front, France gets attacked by Italy, Germany and Belgium, in 1918 gives up.
Great European War
This war is equivalent to WWI, without the belligerence of the U.S.A.
Main article: Great European War
In 1914, Austria-Hungary declares the war to Serbia because, the archduke, Franz Ferdinand, an inheritor for the Austro-Hungarian throne was assassinated in Sarajevo by a Serbian nationalist, immediately, Austria-Hungary mobilizes his troops to the Serbian limits but Russia, an ally of Serbia, also mobilized its troops against Austria-Hungary and Germany causing a tension between the powers. Years ago, in 1900, Denmark, Belgium and the Netherlands joined to the Triple Alliance, consummating the Central Powers, increasing the german influence in Europe.
The official attacks between the alliances start on 28th July of 1914, when France invades Belgium and Luxembourg, causing the war declaratory from Germany, the Netherlands, Italy, Denmark and Austria-Hungary to France, likewise the declaratory of United Kingdom and Russia to the Central Powers.
In 1915, the war is stalled on the western front, in the trench wars. But in 1916, after a series of small german victories, finally Germany and Italy finally manage to advance within french and belgian territory, winning battles in Mons, Flanders and Reims.
Officially, in June of 1917, only France and the United Kingdom continued fighting against the Central Powers. The war is for the alliend powers and France signs an armistice in November of 1918, the United Kingdom agrees the peace with Germany in December of same year.
Claims of the Central Powers
After the war, the France and UK gave their colonies to the Central Powers, the repartition was made according to its war effort, Germany received the majority of british and portuguese territories and kept India like a puppet state, Italy claimed the French Indochina, Algeria and Tunez ad Austria-Hungary annexed the French Western Africa.
Canada, Australia, New Zealand and South Africa were declared completely independent.