[Solved]-Highcharts - connect points with a line in scatter plot on hover-Highcharts

You can use scatter serie with lineWidth set as 2, then hide a SVG path (line) and catch mouseOver / mouseOut events to manipulate graphic.

Example:

http://jsfiddle.net/sbochan/t96cds7o/3/

plotOptions: {
            series: {
                point: {
                    events: {
                        mouseOver: function () {
                            this.series.graph.show();
                        }
                    }
                },
                events: {
                    mouseOut: function () {
                        this.graph.hide();
                    }
                }
            }
        },

 // callback
 setTimeout(function(){
        chart.series[0].graph.hide();
 },1);