What happens when both the parties are absent in a original suit trials for a long time ?

Absence of plaintiff from proceeding would attract passing the order of 'dismissal in default". whereas absence of defendant shall be proceeding the case as "ex-parte".

Your facts and query is contradictory in itself which make it like an examination hall question paper and not a real story.

Court may proceed for dismissal of  suit when both the parties do not appear on hearing date.

Dismissal is the only option in such case.

The court may dismiss for default that means suit is not ended he may again file application for restoration of suit on suitable grounds so you attend court lead evidence ,press the court to close evidence on plaintiff side and permit to lead respondents evidence.

When neither the plaintiff nor the defendant appears before the court when the suit is called for hearing, then the court is empowered to dismiss the suit under Rule 3 of Order IX.04-

In case the plaintiff starts attending and you as well as your lawyer remain in a bliss that the suit may be dismissed due to non-prosecution the it may happen that there may be ex-parte against you.