What follows is 100% speculation; I am not saying what follows is likely to happen, though step 1 looks likely. I desperately hope none of it takes place.
1. Israel launches a ground assault into Gaza.
2. Hezbollah launches further rocket attacks on Israel.
3. Israel bombs and/or invades Southern Lebanon.
4. Iran increases military support to Hezbollah.
5. The US bombs weapons factories in Iran and/or related logistics.
6. Sympathetic Arab countries reduce oil supplies to the West.
7. The Straits of Hormuz become too dangerous for shipping.
8. The US Navy is too stretched to defend shipping at the Bab-al-Mandab Strait from rocket attacks launched in Iran-backed areas of Yemen.
9. The Suez Canal is closed.
10. With important shipping routes out of action, China sees nothing to lose and invades Taiwan.
11. With the US stretched on three fronts, Russia invades the Baltic States.
12. With nobody with spare resources to assist Pakistan, India begins a war.
13. The fiat currency system finally collapses under the strain.
14. Loss of shipping and global financial collapse cause food supplies to fail worldwide.
15. WMDs are deployed
With tanks and APCs building up east of Gaza, I think step 1 looks highly likely now. With four Hezbollah fighters killed by Israel, tension is ratcheting at the Lebanese border, and 2—4 could escalate rapidly. Step 5 is crucial. Netanyahu’s rhetoric indicates that he is trying to draw the US into a conflict with Iran, and it is here that the US, with a carrier en route to the Eastern Mediterranean, must resist worsening the situation (though Netanyahu could unilaterally bomb Iran).
Removing 10—12 might not prevent 13—15, and many other problems could also be factored in; for example, Turkey closes the Bosporus, North Korea and Japan go to war, or there are increased problems on the Mexico-US border … use your imagination.
Again, this is all speculation. Nevertheless, tensions are high; everybody must show enormous restraint to prevent dangerous escalation.
No one knows the future, but WWIII -- or perhaps "WW 2-and-a-half" -- can't be ruled out.
So, what to do? (1) Prepare. Make sure you and your family could remain indoors for a few weeks, if necessary, should the air outside be filled with radioactive fallout/bio-warfare agents, or should it be dangerous to venture out onto the mean streets to stand in long queues for dwindling stocks from a disrupted supply chain. Consider how you would cope with no electricity, no gas, no (safe) water. A bit of planning ahead and some stocking up could make a real difference. (2) Organize. A group of ten people who can communicate with each other via $20 Baofengs, who've organized a rota for 24-hour alerts, prior to any event, and 24-hour neighborhood watches after one, will greatly leverage the preparedness of each individual. Now is not the time to be subject to 'Normalcy Bias'.
[ https://en.wikipedia.org/wiki/Normalcy_bias ]
10-11-12 are severely unlikely. I believe that most likely Russia and China would prefer to stay on the sidelines and let it all run its course. They both think much more strategically and longer term than the West.