The Ember has to be taken out before it gets to four pips. If that's not possible, use a Quench spell to neutralize its attack until it can be destroyed. If no Fire wizard is present, it would help to have several Quence treasure cards in the sideboard.
It's also possible to buy the 90% Fire Shield treasure cards at the Bazaar and put one on the Life Wizard so that he/she can survive the attack and bring everybody back with Rebirth.
There are walkthroughs and FAQs for this tower on Wizard101 Central.
What i like to do is cast a feint on turn 3, so when the ember casts his meteor, i get hit for 13,000 points and die horribly, but tweetybird's advice seems to work better from a winning perspective. -elijah darkthorn, legendary conjurer and, yes, briskbreeze champion