This is one of three possible plays one can go through in the opera house.  When Barnes, the NPC whom starts the event, beings making his speech he gives one of three sets of dialogue, depending on the lines said this will determine what event you face.

This is the dialogue for Romulo and Julianne:

Tonight… we explore a tale of forbidden love!

But beware, for not all love stories end happily, as you may find out.  Sometimes love pricks like a thorn!

But don’t take it from me; see for yourself what tragedy lies ahead when the paths of star crossed lovers meet! And now… on with the show!

This play will have you squaring off against first a lone Romulo and Julianne, and then both of them at the same time.  The solo fights are fairly easy to complete what with each being solely focused upon one path, damage or healing, and therefore easy to counter when on their own.

It’s when they team up that it truly becomes more than a simple annoyance to kill either one, Romulo being a demon in melee combat, dealing in great quantities of pain, whereas Julianne is a CC’er and healer of high quality.

To add even more to the complications, you’ll have to kill them both within ten seconds lest they resurrect, much like core hounds from molten core, and force you to face them once more.

Julianne

The main healer and generally annoying member of the dynamic duo you face, Julianne has quite a few nasty spells she loves to utilize that can often destroy your attempts to end the fight within a timely fashion or even at all.  Keep detect magic on her at all times to be ready to take down her buffs at a moment’s notice.

Eternal Affection

The greatest of Julianne’s healing spells; this is capable of healing her target for up to 50K health in but two seconds of cast time.  Keep your interrupters on guard for this spell over all others.

Powerful Attraction

A ranged incapacitation spell taking the target out of commission for six seconds.

Devotion

A powerful holy buff that Julianne will place upon herself.  This increases her holy damage by 50% and more so increases her cast speed by 50% as well.  This buff has to be destroyed by whatever means necessary as it makes it nigh impossible to prevent her greater healing spells from getting off.

Blinding Passion

This is a holy bolt that’s fired randomly at a raid member, dealing around 1500 a hit and a slight DoT effect of 750 for three more seconds.  This is a two seconds cast time as well, making it easy enough to interrupt should you have the silences or whatever to spare.

Romulo

The main damage lead of the fight, utilizing a number of melee attacks to bring the pain.

Deadly Swathe

A frontal cleave attack that hits up to a maximum of three target for somewhere around 3500 damage, this can be avoid by standing at the side of the boss.

Backwards Lunge

A backwards aimed cleave attack that also hits for 3500 damage or so as well as a knockback effect.  This can be avoided much like the frontal cleave by standing at the side of the boss.

Daring

A massive self-buff that increases both physical damage and attack speed by 35%, similar in fashion to Juliannes own devotion buff.  This should as well be removed as quickly as possible due to the massive amount of damage possible with it going, making him capable of dropping even tanks should they not be immensely well protected.

Poisoned Thrust

This attack debuffs the target with a poison that reduces all stats by 10% and is capable of stacking up to a total of eight times.  Remove this as quickly as possible with cleanse to avoid your tank losing all ability to survive.

The Fight

When the curtain has pulled up Julianne will be revealed to be standing in the center stage, the main tank should have a brief moment to grab her attention before she begins her not so deadly attack upon the raid.
Have the tank pull her to one side of the stage, right or left, and tank her there.

Phase One

Once the tank has Julianne in position on a side of the stage the raid should move in to burn her down.  Have your interrupters keeping watch for Eternal Affection above all others and use this as practice for the third phase where it counts that much more.

Secondly, keep the Devotion buff off her at all times to prevent her getting any heals off, do this correctly and she’ll drop in no time at all.
Once Julianne hits 1% she drinks her poison and ends her life, use this time to move back to center stage and prepare for Romulo’s appearance in this fight.

Phase Two

This has Romulo appearing, the main tank will also have to quickly grab him and pull him off to either right or left side away from where Julianne was tanked.  Once this is accomplished, it’s all tank n’ spank fight time.

The main thing to watch for is his Daring buff as it allows him to pour on the pain, other than that this guys rather easy should your paladins and shamans keep the poisoned thrust debuff off the tank and everyone in melee range besides the tank stand at his sides.

Doing so allows you to avoid all cleave attacks whether forwards or backwards and keep from taking nigh any damage whatsoever. 
Romulo will also drop rather easily, once he hits somewhere around 5% have the tank pull him to the opposite side of where Julianne died.
Once he goes down Phase three begins.

Phase Three

Once Romulo has died both he and Julianne will now proceed to join forces and fight you as a deadly team.  They come back to life in the exact positioning, within which they died, the separation of their corpses allows your tanks to easily grab the required target and begin tanking.

For this phase of the fight you should have the raid break into two groups, each devoted to taking down a single boss and keeping them locked down as far as buffs/special abilities or spells go.  Put as many interrupters as you can on Julianne as her big heal really hurts, and throw any extra healers you might have on the Romulo tank to prevent them getting taken down to easily.

Sometimes you might need a player or two whom can switch back and forth to keep a lock on possible buffs and eliminate them accordingly.

Should everything go well your groups will have both the bosses down to easily killable health levels at the same time, however should this not happen just focus fire them as needed to even the health ratios out.

Once the bosses hit 10% become extremely careful about evenly dropping their health, bringing them down steadily to somewhere around 5% health before pouring on the damage to bring them down within the ten second mark.

If you keep on the ball with buffs, debuffs, cleansing, and so on you should be capable of dropping the duo quite easily.