It's Monday, it's a new week, and while we won't pretend to know everything that's going to happen over the next seven days, we have some sense of what's coming up.

Here's your briefing on some of the most important and interesting stories happening in the week ahead.

1) Tension at the G20

Image copyright Reuters Image caption Mohammed bin Salman and Emmanuel Macron happily shaking hands back in April

What's happening?

The G20 summit of the world's most powerful leaders begins in Buenos Aires on Friday.

Why does it matter?

There's always some sort of intrigue or tension behind the scenes of the G20 (last year's - Donald Trump's first - was especially awkward). This year, it will be raised to a new level.

This year, it looks almost certain that Saudi Arabia's Crown Prince Mohammed bin Salman will attend. But he will do so amid accusations he ordered the killing of journalist Jamal Khashoggi.

This is the likely conclusion that US officials have reached, but the US president seems less keen to definitively say this is what happened.

Mr Trump will attend, as will Germany's Angela Merkel (who has attacked the Saudi explanation for the murder), France's Emmanuel Macron (whose country imposed travel bans on people suspected of being responsible for the killing) and Turkey's Recep Tayyip Erdogan (in whose country the murder took place, and from where information incriminating Saudi Arabia has leaked).

Plenty of world leaders will not want to be caught in photo opportunities cosying up to the crown prince. And plenty could happen on the sidelines, the consequences of which will slowly become clear.

2) Lights out on one island?

Image copyright Getty Images

What's happening?

All the electricity on one British island could be turned off at the end of the week.

Why does it matter?

About 500 people live on the island of Sark in the English Channel, and one official there says they will all have to adopt "a bit of a wartime mentality" from this week.

On Friday, the island's electricity provider will withdraw its services. This is because it was ordered to reduce its prices earlier this year, a situation it says has caused it to lose a significant amount of money.

There was some concern all the residents may be forced to evacuate, but that looks unlikely to happen now. But they are having to find whatever alternative they can to keep the lights on - including an emergency generator and a plan to share whatever renewable energy is created on the island.

3) All eyes on Mississippi

What's happening?

Three weeks on, the US mid-term elections are still not over. When people in Mississippi voted to pick one of the state's two senators on 6 November, no one candidate gained an overall majority. So now there will be another vote.

Why does it matter?

After the mid-terms, with Mississippi undecided, Republicans have 52 Senate seats, and Democrats 47 (including two independents who vote with them). Whatever happens on Tuesday, Republicans will still have more seats, but if Democrats are able to flip this seat in Mississippi, it could make it just a bit more complicated for Donald Trump's agenda to pass through the Senate.

Republican contender Cindy Hyde-Smith hasn't made things particularly easy for herself in the past few weeks, especially if she had any hope of capturing African-American votes.

First, she was filmed making a joke about public hangings, in a state where African-Americans were lynched in the past (Hyde-Smith later apologised for any offence caused).

Then, she appeared to crack another joke, about trying to suppress the registration of some of her opponent's voters.

The opponent in question, Mike Espy, would be the first African-American senator in Mississippi. And while it's still unlikely Espy will win, President Trump is coming to town to support his candidate. Just in case.

4) Crunch moment for climate

What's happening?

The 24th UN Climate Change Conference starts in Katowice, Poland, on Sunday.

Why does it matter?

Back in 2015, in a historic deal, world leaders agreed a framework for combating climate change. Three years on, they're still struggling to agree how to put that plan into practice, and the Katowice talks hope to move the discussion further along.

For those developing countries keen for financial help to battle a worsening climate, time is of the essence.

The task has been made even more difficult by President Trump saying he intends to withdraw the US from the pact.

But now, it's also been reported that the Trump administration will host a side-event promoting the use of fossil fuels, as they did during last year's talks in Bonn, Germany.

It didn't go down very well then, either.

5) Clash of the titans

Image copyright Getty Images Image caption British heavyweight Tyson Fury (L) is confronted by Deontay Wilder

What's happening?

American boxer Deontay Wilder will put his world heavyweight championship on the line against Tyson Fury on Saturday.

Why does it matter?

If you're into boxing, this is the real deal: one of the most hotly-anticipated heavyweight bouts in years.

Both men are undefeated, and the winner will be at the front of the queue to face Anthony Joshua, who holds the rest of the world heavyweight titles.

If Fury wins in Los Angeles, it would mark the culmination of a remarkable journey.

After becoming world champion in 2015, the Brit spent two and a half years out of the ring, was treated for depression, and (in his own words) "ballooned up to 28 stone (392 lbs)".

Now, he has reportedly lost 10 stone, and says he's in the best shape of his life. On Saturday, the boxing world will find out if that is enough.