From its south-eastern to its north-western-most corners in Greece and Scotland, there are battles raging over the future of the European Union – and Germany has a finger in every pie.
European Council President Donald Tusk said this week that Europe could break apart over the refugee crisis or if Britain quits the Union.
"Handle with care. What is broken cannot be mended," Tusk said on Monday.
Merkel unveiled her plans for this week's summit to MPs on Wednesday – and it's one of her thorniest-ever to-do lists.
1. Germany must help Britain get a good deal
Prime Minister David Cameron is coming to Brussels with a different agenda than everyone else.
While Germany is preparing for a dustup with eastern and southern Europe over how to manage refugee flows, Cameron is hoping to nail down a new deal for the UK that will convince voters to vote for "In" at an upcoming referendum.
Germany has been the target of intense diplomacy from the UK in recent months, culminating in last week's Matthiae banquet in Hamburg, which saw Merkel dine alongside Cameron in the historic trading port.
Merkel has been the target of British diplomacy like no other European leader in recent months. Photo: DPA
That's brought Merkel to agreement with Cameron on many points – like the need to protect national social systems from abuse and a bigger say for national parliaments on EU rules.
Merkel thinks that "our job is simply to provide the British government with the best arguments for remaining in a reformed EU".
"Britain is a strong partner in the [European] internal market and for engagement abroad and in the world," she told MPs in Berlin to loud applause.
But the Chancellor will only hand Cameron what he wants up to a point.
Freedom of movement and non-discrimination among different EU nationalities are "basic principles" of the EU that cannot be challenged, she insisted.
Ultimately, "all sides can be satisfied" if everyone is ready to make compromises, Merkel believes.
She can only hope that others will approach the meeting in the same spirit – because that's the only way she'll be able to tackle the next three points...
2. Fight causes of flight
If the number of refugees arriving in Europe is to be reduced, the EU has to throw its weight into solving the Syrian and other conflicts in the Middle East and making life bearable for refugees closer to their homes.
Merkel said that "the current situation is unbearable" in Syria, blaming Russian airstrikes and Syrian troops' actions for worsening conditions for civilians in many of the bloodied country's cities.
She welcomed last week's agreement for a possible ceasefire and repeated her belief that a no-fly zone must be agreed to protect civilians and as a first step in a negotiated peace.
But for Merkel, improving conditions for refugees in neighbouring countries like Turkey, Jordan and Lebanon will reduce the pressure to head for Europe.
"Conditions must become better in Jordan and Lebanon – which has one million refugees and five million inhabitants," she reminded parliamentarians.
"You can imagine what that's like for a country like Lebanon, pulled here and there by conflicts in the region."
That's why she trumpeted Germany's big donation to the World Food Programme last month – part of "the most successful donor conference in the history of the UN" – and called on Europe to finally unlock €3 billion in aid promised to Turkey.
Turkey's granting work permits for Syrians will also make more refugees think twice before making the dangerous trip to Europe, she said.
3. Protect the EU's external border
In fact, many of Merkel's plans depend on close co-operation with Turkey.
"We have to learn to protect the maritime borders of the European Union," she said, rubbishing eastern European calls to build a border fence in Macedonia to prevent refugees travelling north from Greece.
German Navy ship Bonn is leading the NATO mission to the Aegean sea. Photo: DPA
"A continent that can't agree with its neighbours about this, that hides behind fences some distance back from the real border, that can't be the European solution. I am firmly convinced of that," Merkel went on.
So in Brussels, she'll be pushing her plan to work more closely with Turkey – sending NATO ships to patrol the Aegean for people-smugglers' boats, exchanging data with Turkish police, and sending refugees back there if they are rescued at sea – in opposition to eastern European hopes of giving up on Greece.
4. Control refugees already here
Merkel says that a lot has already been done to bring the refugee situation under control within Germany's borders.
The government is declaring more states "safe countries of origin" whose citizens can't apply for asylum without showing exceptional circumstances.
Police in an asylum home in Ellwangen, Baden-Württemberg, in January. Photo: DPA
A faster procedure aims to get asylum applications approved or rejected faster, while Merkel and her ministers have agreed new measures to expel criminal asylum seekers more quickly.
But she added that she believes public opinion in still behind her.
"Those who need and seek protection should get it. More than 90 percent of the German public continue to say anyone fleeing war, terror or persecution should find welcome and protection in Germany.
"I find that wonderful," she said.
5. Make the EU look competent
"People inside and outside Europe must get the impression that it can overcome its problems without damaging itself," Merkel said bluntly from the rostrum of the Bundestag on Wednesday.
Her task is just as much about showing the public at home and observers abroad that the German government and its neighbours can agree on marshalling Europe's vast resources to address the refugee crisis – just as they have done at successive crunch financial summits since 2008.
"This is a step on the way that Europe has been taking and getting stronger," Merkel said.
"A stronger Europe means a stronger Germany, better able to – to quote the Finance Minister [Wolfgang Schäuble] – withstand its rendezvous with globalization."