Use the correct form of verb …

To answer this question, we need to understand some concepts about conditional statements.

There are three types of conditions :

I) Condition possible to fulfill.

II) Condition in theory possible to fulfill.

III) Condition not possible to fulfill.

CONDITIONS WITH (IF CLAUSE)

I) Simple present (first part) Will - future or modal + affirmative (second part)

II) Simple past (first part) would + infinitive ( second part)

III) Past perfect ( first part) would + have + past participle ( second part)

The Roman numbers represent condition one, two and three. 
Examples in negative and affirmative
If I don't study, I will fail in exams. 

For the question above we will find the appropriate verb that completes the sentence but we know the second part will have a 'will ' in positive form.

ANSWERING THE GIVEN QUESTION :

If I don't go to Anu's party tonight, I will remain in the house.