As a morning train brings Kejriwal into this ancient city on the banks of the Ganges, around 350 young men and women spread out in Varanasi are planning a "phaadu debut" (rocking debut) for their leader.
This team of 25-something is busy tailoring a locally-flavoured winning strategy which they say will "humble" Modi when the Hindu holy city votes for its next Lok Sabha representative May 12.
And as they speak of a "99 percent surety" of the former Delhi chief minister taking on the BJP heavyweight, they say confidently that the AAP leader will preside over the BJP's political waterloo.
There is a team of volunteers led by Saman Qureshi from New Delhi which is holding 20-minute 'nukkad nataks', largely near the Beniyabagh ground where Kejriwal will hold his rally Tuesday.
Kejriwal will also visit the Kashi Vishwanath temple.
Saman, a niece of former chief election commissioner S.Y. Qureshi, told IANS that by Monday evening they would have completed 150 street skits in just 10 days.
"Through these skits we tell people about the value of electing the right candidate and take up the cause of the anti-corruption movement. We stress that their vote can make all the difference," she said.
Other volunteers in the 'nukkad natak' group come from Allahabad, Varanasi and Lucknow.
A former income tax officer-turned-activist-turned-politician, Kejriwal is likely to hold a 'referendum' at the rally Tuesday seeking people's approval for his decision to take on Modi.
The die, however, has been cast and it is just a matter of a formal announcement, said an insider in the Aam Aadmi Party team.
For the 350-odd volunteers now in Varanasi who depend on complimentary accommodation and food from locals, it is time to get cracking.
Vaibhav Maheshwari, who handles the media for the AAP in Uttar Pradesh, says the Kejriwal-Modi battle will not be just symbolism.
Leaving a fledgling IT business in Lucknow and an angry wife who has to handle two kids and home all by herself in his absence, the 38-year-old Maheshwari says that the outcome of the Modi-Kejriwal contest would be a watershed -- and stunning.
He points to two types of people in the temple town -- the elite and erudite rooting for Modi and a big chunk of have not's who see Kejriwal as a beacon of hope.
"We have taken up issues like poor drainage, law and order, unplanned city planning, corruption, non-performance of past BJP representatives in the Lok Sabha, assembly and the municipal corporation for the present mess as the theme in our bulk mailers and social media discourse," says Aniket Saxena of Lucknow.
A one-of-its-kind 'Buzz' campaign is also underway in Varanasi.
In this, volunteers, as they explained to IANS, stand at important interactions and busy thoroughfares, for two hours, carrying banners with slogans favouring AAP.
They neither speak nor interact with anyone but just attract the attention of commuters.
Nandan Mishra, an IIT-Kanpur alumni who left a lucrative Citibank job to be "in the thick of things" with AAP, leads the 'Play for Change' - a music group which plays oldies like 'Raghupati Raghav Raja Ram' and 'Hum Honge Kamyaab' (We Shall Overcome) tunes in the narrow lanes.
This group plays music on violin and guitar and does not speak to people. A team following them distributes pamphlets and literature of AAP.
Ujjwal Modi, a chartered accountant from Jhansi who keeps a tab on the AAP's election expenditure, finds Varanasi "all geared up with their soul and purse" for the party.
"People here are not only generous but politically very aware," he says, while admitting the party's shoestring budget.
Party sources say Kejriwal, soon after reaching Varanasi, will drive to the Kaal Bhairav temple. Bhairav is the 'shahr kotwal' (city inspector), and everyone seek his blessings before a new venture.
Kejriwal will then visit the Kashi Vishwanath temple, perhaps the city's best known temple.
He will interact with morning walkers at some parks, besides calling on retired academics and current professors at the Banaras Hindu University.
For the former chief minister of Delhi, battle Varanasi will be no less than an epic battle.