return {
    'ThePrimeagen/harpoon',
    config = function(_, opts)
        require('harpoon').setup(opts)
        local mark = require('harpoon'.. ".mark")
        local ui = require('harpoon'.. ".ui")

        -- Harpoon marked files 1 through 4.
        vim.keymap.set("n", "<a-1>", function() ui.nav_file(1) end)
        vim.keymap.set("n", "<a-2>", function() ui.nav_file(2) end)
        vim.keymap.set("n", "<a-3>", function() ui.nav_file(3) end)
        vim.keymap.set("n", "<a-4>", function() ui.nav_file(4) end)

        -- Harpoon next and previous.
        vim.keymap.set("n", "<a-n>", function() ui.nav_next() end)
        vim.keymap.set("n", "<a-p>", function() ui.nav_prev() end)

        -- Harpoon user interface.
        vim.keymap.set("n", "<leader>hq", ui.toggle_quick_menu)
        vim.keymap.set("n", "<leader>ha", mark.add_file)

    end
}